Answer:
The wavelength is 3500 nm.
Explanation:
d= [tex]\frac{1}{700 lines per mm} = 0.007mm = 7000 nm[/tex]
n= 1
θ= 30°
λ= unknown
Solution:
d sinθ = nλ
λ = [tex]\frac{7000 nm sin 30}{1}[/tex]
λ = 3500 nm
A turntable is off and is not spinning. A 0.8 g ant is on the disc and is 9 cm away from the center. The turntable is turned on and 0.8 s later it has an angular speed of 45 rpm. Assume the angular acceleration is constant and determine the quantities for the ant 0.4 s after the turntable has been turned on. Express all quantities using appropriate mks units.
Answer:
I] alpha = wf/t = (45*2pi/60)/1 = 4.712 rad/s
ii] W = alpha*t = 2.356 rad/s
iii] v = Wr =2.356*0.10 = 0.2356 m/s
iv] atan = alpha*r = 0.4712 m/s^2
v] arad= v^2/r = 0.2356^2/0.10 = 0.555 m/s^2
vi] a = sqrt(0.4712^2+0.555^2) = 0.728 m/s^2
vii] Fnet = ma = 1.6e-3*0.728 = 0.00116 N
Explanation:
1. (4 pts) We use Fst to measure the number of migrants per generation (Nm) by assuming a balance between the effects of a differentiating evolutionary force and a cohesive evolutionary force. Name those two forces. (Hint, think of the computer simulations of migration)
Answer:
This structure is determined by the combined effect of deterministic forces and stochastic forces.
Explanation:
Genetic drift refers to random fluctuations in allele frequencies due to chance events , a stochastic (random) force which scrambles the predictable effects of selection, mutation, and gene flow.
Genetic drift is not a potent evolutionary force in very large randomly mating populations. to illustrate the consequences of genetic drift we will consider what happens when drift alone is altering the frequencies of alleles among many small populations. To prove this, we need to understand Population structure, which describes how individuals (or allele frequencies) in breeding populations vary in time and space.
A particle of mass m= 2.5 kg has velocity of v = 2 i m/s, when it is at the origin (0,0). Determine the z- component of the angular momentum of the particle about each of the following reference points. The coordinates of the reference points have units of (meters, meters). Assume the positive z-axis is directed out of the screen. Randomized Variables m= 2.5 kg v = 2 i m/sPart (a) Determine the angular momentum in kg.m-/s of the particle about (0,1). Part (b) Determine the angular momentum in kgm/s of the particle about (0, -1). Part (c) Determine the angular momentum in kg.m-/s of the particle about (1,0).Part (d) Determine the angular momentum in kg.m/s of the particle about (-1,0). Part (e) Determine the angular momentum in kg. m²/s of the particle about (1,1). Part (f) Determine the angular momentum in kg ·mº/s of the particle about (-1,1). Part (g) Determine the angular momentum in kg.mʻls of the particle about (-1,-1).Part (h) Determine the angular momentum in kg.m-/s of the particle about (1,-1). Part (i) Determine the angular momentum in kg.m/s of the particle about (0,0).
Answer:
please read the answer below
Explanation:
The angular momentum is given by
[tex]|\vec{L}|=|\vec{r}\ X \ \vec{p}|=m(rvsin\theta)[/tex]
By taking into account the angles between the vectors r and v in each case we obtain:
a)
v=(2,0)
r=(0,1)
angle = 90°
[tex]L=(2.5kg)(1)(2\frac{m}{s})sin90\°=5.0kg\frac{m}{s}[/tex]
b)
r=(0,-1)
angle = 90°
[tex]L=(2.5kg)(1)(2\frac{m}{s})sin90\°=5.0kg\frac{m}{s}[/tex]
c)
r=(1,0)
angle = 0°
r and v are parallel
L = 0kgm/s
d)
r=(-1,0)
angle = 180°
r and v are parallel
L = 0kgm/s
e)
r=(1,1)
angle = 45°
[tex]L = (2.5kg)(2\frac{m}{s})(\sqrt{2})sin45\°=5kg\frac{m}{s}[/tex]
f)
r=(-1,1)
angle = 45°
the same as e):
L = 5kgm/s
g)
r=(-1,-1)
angle = 135°
[tex]L=(2.5kg)(2\frac{m}{s})(\sqrt{2})sin135\°=5kg\frac{m}{s}[/tex]
h)
r=(1,-1)
angle = 135°
the same as g):
L = 5kgm/s
hope this helps!!
The determinant method allows to find the z component of the angular momentum for the particle moving in the x axis are:
a) L_z = - 5.0 kg m / s
b) L_z = 5 kg m/s
c) L_z = 0
d) L_z = 0
e) L_z = -5.0 kg m / s
f) L_z = 5.0 kg / ms
g) L_z = 5.0 kg m / s
The angular momentum is defined by the vector product of the position and the linear momentum, therefore it is a vector quantity.
L = r x p
Where the bold letters represent vectors, L the angular momentum, r the position and p the linear moment
Momentum is defined by.
p = m v
where m is the mass.
The modulus of angular momentum is:
L = m r v sin θ
One way to find the angular momentum in various dimensions is to solve for the determinant method.
[tex]L = m \ \left[\begin{array}{ccc}i&j&k\\x&y&z\\v_x&v_y&v_z\end{array}\right][/tex]
The component z of the angular momentum is
[tex]L_z = m ( x v_y - y v_x)[/tex]
Indicate that the mass of the body is m = 2.5 kg and it moves in the direction x, v = 2 i m/s, let's calculate the angular momentum in direction z for each case:
The velocity is v = 2i
a) point r = (0,1)
[tex]L_z[/tex] = - 2,5 1 2
L_z = - 5.0 kg m / s
b) point r = (0, -1)
L_z = -2.5 (-1) 2
L_z = 5 kg m/s
c) point r = (1,0)
L_z = 2,5 0 2
L_z = 0
velocity is parallel to position
d) point r = (-1,0)
L_z = 0
Velocity is parallel to position
e) point r = (1,1)
L_z= 2.5 (1 0 - 2 1)
L_z = -5.0 kg m / s
f) point r = (- 1, -1)
L_z = 2.5 (1 0 - 2 (-1))
L_z = 5.0 kg / ms
g) point r = (1, -1)
L_z = 2,5 (1 0 - 2 (-1))
L_z = 5.0 kg m / s
In conclusion using the determinant method we can find the z component of the angular momentum for the particle moving in the x axis are:
a) L_z = - 5.0 kg m / s
b) L_z = 5 kg m/s
c) L_z = 0
d) L_z = 0
e) L_z = -5.0 kg m / s
f) L_z = 5.0 kg / ms
g) L_z = 5.0 kg m / s
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A 6.0 m wire with a mass of 50 g, is under tension. A transverse wave, for which the frequency is 810 Hz, the wavelength is 0.40 m, and the amplitude is 4.0 mm, is propagating on the wire. a) How long will it take for a crest of this wave to travel the length of the wire? b) What is the tension in the wire?
Answer:
a) t = 0.0185 s = 18.5 ms
b) T = 874.8 N
Explanation:
a)
First we find the seed of wave:
v = fλ
where,
v = speed of wave
f = frequency = 810 Hz
λ = wavelength = 0.4 m
Therefore,
v = (810 Hz)(0.4 m)
v = 324 m/s
Now,
v = L/t
where,
L = length of wire = 6 m
t = time taken by wave to travel length of wire
Therefore,
324 m/s = 6 m/t
t = (6 m)/(324 m/s)
t = 0.0185 s = 18.5 ms
b)
From the formula of fundamental frquency, we know that:
Fundamental Frequency = v/2L = (1/2L)(√T/μ)
v = √(T/μ)
where,
T = tension in string
μ = linear mass density of wire = m/L = 0.05 kg/6 m = 8.33 x 10⁻³ k gm⁻¹
Therefore,
324 m/s = √(T/8.33 x 10⁻³ k gm⁻¹)
(324 m/s)² = T/8.33 x 10⁻³ k gm⁻¹
T = 874.8 N
Homework 7 Adaptive Follow-Up Problem 25.68 Item 4 Constants A cylindrical copper cable 3.30 km long is connected across a 220.0-V potential difference. Part A What should be its diameter so that it produces heat at a rate of 50.0 W ? Express your answer with the appropriate units. TemplatesSymbols undoredoresetkeyboard shortcutshelp D = nothing nothing Request Answer Part B What is the electric field inside the cable under these conditions? Express your answer with the appropriate units. TemplatesSymbols undoredoresetkeyboard shortcutshelp E = nothing nothing Request Answer Provide Feedback
First, we calculate the current through the cable using given Power and Voltage. Then, we use this current to find the resistance and subsequently, the diameter of the cable. For Part B, the electric field inside a cable is zero in steady state conditions.
Explanation:To solve Part A of the question, we will use the formula Power = I2R, where I is current and R is resistance. First, we find the Current from the given power and voltage, Power = Voltage * Current. Second, we use this current to calculate the resistance, R = Power / I2. Lastly, we find the diameter using the formula for the Resistance of a cylindrical conductor, R = rho * L / A, where rho is resistivity, L is length and A is area. For Part B, the electric field inside a conductor under steady state conditions is zero.
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The diameter of the copper wire can be determined by solving an equation using its cross-sectional area. The electric field inside the copper wire is calculated by dividing the potential difference by the distance.
Explanation:The question pertains to calculating the diameter of a cylindrical copper cable and the electric field inside it given certain conditions. This involves the use of formulas related to the principles of electromagnetism, and specifically electric current and electric field.
In order to determine the diameter of the cable (Part A), we would first need to deduce the cross-sectional area using data provided. The formula AD² = 4 could be used, where A represents the cross-sectional area and D the diameter of the cable. Substituting the value found for area, we can solve for the diameter.
For Part B, the electric field inside the cable can be calculated using the formula E = V/d, where V is the potential difference and d is the distance. Given that the potential difference is 220V and the length or distance is 3.3 km, the desired electric field can be computed.
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A certain elastic conducting material is stretched into a circular loop of 12.0 cm radius. It is placed with its plane perpendicular to a uniform 0.800 T magnetic field. When released, the radius of the loop starts to shrink at an instantaneous rate of 75.0 cm/s . What emf is induced in the loop at that instant
Answer:
The induced emf in the loop is 0.452 volts.
Explanation:
Given that,
Radius of the circular loop, r = 12 cm = 0.012 m
Magnetic field, B = 0.8 T
When released, the radius of the loop starts to shrink at an instantaneous rate of, [tex]\dfrac{dr}{dt}=75\ cm/s=0.75\ m/s[/tex]
The induced emf in the loop is equal to the rate of change of magnetic flux. It is given by :
[tex]\epsilon=\dfrac{-d\phi}{dt}\\\\\epsilon=\dfrac{-d(BA)}{dt}\\\\\epsilon=B\dfrac{-d(\pi r^2)}{dt}\\\\\epsilon=2\pi rB\dfrac{-dr}{dt}\\\\\epsilon=2\pi \times 0.12\times 0.8\times 0.75\\\\\epsilon=0.452\ V[/tex]
So, the induced emf in the loop is 0.452 volts.
A circuit contains two inductors of 6.0 mH inductance in parallel placed in series with an inductor of 8.0 mH inductance. After one of the 6.0 mH inductors burns out, the repairman wants to replace all three inductors with one inductor of equivalent inductance. Assuming inductors combine in series and parallel the same way resistors do, what inductance should he use
Answer:
Check attachment for circuit diagram
And better understanding
Explanation:
Let find the equivalent inductance.
The 6mH in parallel to 6mH
Parallel connection will give
1 / Leq = 1 / L1 + 1 / L2
L1 = L2 = L = 6mH
1 / Leq = 1 / 6 + 1 / 6
1 / Leq = 2 / 6
1 / Leq = 1 / 3
Then, take reciprocal
Leq = 3 mH
Now the combInation of this parallel connection is connect in series with an 8mH inductor
Series connection is given as
Leq = L1 + L2
So, the equivalent of the parallel connection is 3mH and this will be connect in series with 8mH
Then, final inductance is
Leq = 3 + 8
Leq = 11 mH
Therefore, the repairman need to replace the element with one inductor of inductance 11 mH.
This question involves the concepts of inductance, series combination, and parallel combination.
The inductance to be used is found to be "11 mH".
RESULTANT INDUCTANCEFirst, we will find out the resultant inductance of the two inductors connected in a parallel combination. Since it is given that inductors behave like resistors in combination. Therefore, resultant of two inductances connected in parallel combination will be:
[tex]\frac{1}{L}=\frac{1}{L_1}+\frac{1}{L_2}[/tex]
where,
L = resultant inductance of the two inductors in parallel combination = ?L₁ = L₂ = inductance of the two inductors = 6 mH = 6 x 10⁻³ HTherefore,
[tex]\frac{1}{L}=\frac{1}{6\ x\ 10^{-3}\ H}+\frac{1}{6\ x\ 10^{-3}\ H}\\\\[/tex]
L = 3 x 10⁻³ H = 3 mH
Now, we will calculate the total inductance of this combination in series combination with the third inductor as follows:
[tex]L_T=L+L_3=3\ mH+8\ mH\\L_T=11\ mH[/tex]
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g A rope, under a tension of 233 N and fixed at both ends, oscillates in a second-harmonic standing wave pattern. The displacement of the rope is given by . where at one end of the rope, is in meters, and is in seconds. What are (a) the length of the rope, (b) the speed of the waves on the rope, and (c) the mass of the rope
Answer with Explanation:
We are given that
Tension=T=233 N
The displacement of the rope is given by
[tex]y=(0.320 m)sin(\frac{\pi x}{3})sin(10\pi)t[/tex]
a.By comparing with
[tex]y=Asin(kx)sin(\omega t)[/tex]
We get
A=0.32
k=[tex]\frac{\pi}{3}[/tex]
[tex]\omega=10\pi[/tex]
[tex]k=\frac{2\pi}{\lambda}[/tex]
[tex]\frac{\pi}{3}=\frac{2\pi}{\lambda}[/tex]
[tex]\lambda=3\times 2=6m[/tex]
n=2
[tex]n\lambda=2L[/tex]
[tex]2\times 6=2L[/tex]
[tex]L=6[/tex]m
b.[tex]\omega=2\pi f[/tex]
[tex]2\pi f=10\pi[/tex]
[tex]f=\frac{10}{2}=5Hz[/tex]
Speed,[tex]v=f\lambda=5\times 6=30m/s[/tex]
c.Let
Mass of the rope=m
[tex]\mu=\frac{m}{L}=\frac{m}{6}[/tex]
[tex]v^2=\frac{T}{\mu}[/tex]
[tex](30)^2=\frac{233}{\frac{m}{6}}[/tex]
[tex]900\times \frac{m}{6}=233[/tex]
[tex]m=\frac{233\times 6}{900}=1.553 kg[/tex]
Construct a parallel-plate capacitor where a second line of charges equal in size and opposite in charge are placed below the line of positive charges. Examine what the "E-field" is like between the plates using a sensor.
A parallel-plate capacitor consists of two plates with opposite charges, creating an electric field between them. The electric field can be measured using an electric field sensor.
Explanation:In a parallel-plate capacitor, a second line of charges equal in size but opposite in charge is placed below the line of positive charges, creating an electric field (E-field) between the plates. The E-field is a vector quantity that points from the positive plate to the negative plate. Its magnitude can be determined using a sensor, such as an electric field sensor, which measures the strength of the electric field.
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A parallel-plate capacitor creates a uniform electric field between its plates, where the field's magnitude is proportional to the surface charge density and directly proportional to the amount of charge on the plates.
Explanation:A parallel-plate capacitor consists of two identical, parallel conducting plates separated by a certain distance. When we create a system where one plate is charged with positive charges and the other with an equal magnitude of negative charges, by, for instance, connecting the plates to the opposite terminals of a battery, an electric field (often referred to as the E-field) is established between the plates. This electric field is extremely uniform because of the geometry of the plates and the even distribution of charges.
The magnitude of the electric field (E) between the plates is proportional to the surface charge density (σ), which is the charge per unit area on a plate. It is described mathematically as E = σ/ε0, where ε0 is the permittivity of free space. The strength of the electric field is also directly proportional to the amount of charge (Q) on the plates. Therefore, when more charge is present on the plates, the electric field will be stronger, illustrated by the increase in the density of field lines that begin on positive charges and end on negative ones.
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When a low-pressure gas of hydrogen atoms is placed in a tube and a large voltage is applied to the end of the tube, the atoms will emit electromagnetic radiation and visible light can be observed. If this light passes through a diffraction grating, the resulting spectrum appears as a pattern of four isolated, sharp parallel lines, called spectral lines. Each spectral line corresponds to one specific wavelength that is present in the light emitted by the source. Such a discrete spectrum is referred to as a line spectrum. By the early 19th century, it was found that discrete spectra were produced by every chemical element in its gaseous state. Even though these spectra were found to share the common feature of appearing as a set of isolated lines, it was observed that each element produces its own unique pattern of lines. This indicated that the light emitted by each element contains a specific set of wavelengths that is characteristic of that element.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value of n is [tex]n =7[/tex]
Explanation:
From the question we are told that
The value of m = 2
For every value of [tex]m, n = m+ 1, m+2,m+3,....[/tex]
The modified version of Balmer's formula is [tex]\frac{1}{\lambda} = R [\frac{1}{m^2} - \frac{1}{n^2} ][/tex]
The Rydberg constant has a value of [tex]R = 1.097 *10^{7} m^{-1}[/tex]
The objective of this solution is to obtain the value of n for which the wavelength of the Balmer series line is smaller than 400nm
For m = 2 and n =3
The wavelength is
[tex]\frac{1}{\lambda } = (1.097 * 10^7)[\frac{1}{2^2} - \frac{1}{3^2} ][/tex]
[tex]\lambda = \frac{1}{1523611.1112}[/tex]
[tex]\lambda = 656nm[/tex]
For m = 2 and n = 4
The wavelength is
[tex]\frac{1}{\lambda } = (1.097 * 10^7)[\frac{1}{2^2} - \frac{1}{4^2} ][/tex]
[tex]\lambda = \frac{1}{2056875}[/tex]
[tex]\lambda = 486nm[/tex]
For m = 2 and n = 5
The wavelength is
[tex]\frac{1}{\lambda } = (1.097 * 10^7)[\frac{1}{2^2} - \frac{1}{5^2} ][/tex]
[tex]\lambda = \frac{1}{2303700}[/tex]
[tex]\lambda = 434nm[/tex]
For m = 2 and n = 6
The wavelength is
[tex]\frac{1}{\lambda } = (1.097 * 10^7)[\frac{1}{2^2} - \frac{1}{6^2} ][/tex]
[tex]\lambda = \frac{1}{2422222}[/tex]
[tex]\lambda = 410nm[/tex]
For m = 2 and n = 7
The wavelength is
[tex]\frac{1}{\lambda } = (1.097 * 10^7)[\frac{1}{2^2} - \frac{1}{7^2} ][/tex]
[tex]\lambda = \frac{1}{2518622}[/tex]
[tex]\lambda = 397nm[/tex]
So the value of n is 7
The rotor of a helicopter is gaining angular speed with constant angular acceleration. At tt = 0 it is rotating at 1.25 rad/srad/s. From tt = 0 to tt = 2.00 ss, the rotor rotates through 8.00 radrad. What is the angular acceleration of the rotor?
Answer:
[tex]2.75\ rad/s^2[/tex]
Explanation:
[tex]\omega_i[/tex] = Initial angular velocity = 1.25 rad/s
[tex]\alpha[/tex] = Angular acceleration
[tex]\theta[/tex] = Angle of rotation = 8 rad
t = Time taken = 2 s
[tex]\theta=\omega_it+\frac{1}{2}\alpha t^2\\\Rightarrow 8=1.25\times 2+\frac{1}{2}\times \alpha\times 2^2\\\Rightarrow \alpha=\dfrac{2}{2^2}(8-1.25\times 2)\\\Rightarrow \alpha=2.75\ rad/s^2[/tex]
The angular acceleration of the rotor is [tex]2.75\ rad/s^2[/tex]
a particle with charge Q is on the y axis a distance a from the origin and a particle with charge qi is on the x axis at a distance d from the origin. The value of d for which the x component of the force on the second particle is the greatest is
Answer:
Explanation:
Force on Q due to q₁
= k Q.q₁ / r² , r is distance between two.
X component
= k Q.q₁ / r² x cos θ , θ is angle r makes with x - axis.
= k Q.q₁ / r² x cos θ
r = a / sinθ
X component
= k Q.q₁ sin²θ . cosθ/ a²
= k Q.q₁ / 2 a² x sin2θ . sinθ
for maximum value of it ,
sin2θ = 1 , θ = 45°
a / d = tan45
a = d .
Why do you suffer more pain than me when I slap your face?
What mass of steam at 100°C must be mixed with 490 g of ice at its melting point, in a thermally insulated container, to produce liquid water at 89.0°C? The specific heat of water is 4186 J/kg·K. The latent heat of fusion is 333 kJ/kg, and the latent heat of vaporization is 2256 kJ/kg.
Answer:
the mass of steam at 100°C must be mixed is 150 g
Explanation:
given information:
ice's mass, [tex]m_{i}[/tex] = 490 g = 0.49 kg
steam temperature, T = 100°C
liquid water temperature, T = 89.0°C
specific heat of water, [tex]c_{w}[/tex] = 4186 J/kg.K = 4.186 kJ/kg.K
latent heat of fusion, [tex]L_{f}[/tex] = 333 kJ/kg
latent heat of vaporization, [tex]L_{v}[/tex] = 2256 kJ/kg
first, we calculate the heat of melted ice to water
Q₁ = [tex]m_{i} L_{f}[/tex]
where
Q = heat
[tex]m_{i}[/tex] = mass of the ice
[tex]L_{f}[/tex] = latent heat of fusion
thus,
Q₁ = [tex]m_{i} L_{f}[/tex]
= 0.49 x 333
= 163.17 kJ
then, the heat needed to increase the temperature of water to 89.0°C
Q₂ = [tex]m_{i}[/tex] [tex]c_{w}[/tex] (89 - 0), the temperature of ice is 0°C
[tex]c_{w}[/tex] = specific heat of water
so,
Q₂ = [tex]m_{i}[/tex] [tex]c_{w}[/tex] (89 - 0)
= 0.49 x 4.186 x 89
= 182.55 kJ
so, the heat absorbed by the ice is
Q = Q₁ + Q₂
= 163.17 + 182.55
= 345.72 kJ
the temperature of the steam is 100°C, so the mass of the steam is
Q = [tex]m_{s}[/tex][tex]L_{v}[/tex] + [tex]m_{s}[/tex][tex]c_{w}[/tex] (100 - 89)
Q = [tex]m_{s}[/tex]([tex]L_{v}[/tex] + [tex]c_{w}[/tex] (11))
[tex]m_{s}[/tex] = Q/ [[tex]L_{v}[/tex] + [tex]c_{w}[/tex] (11)]
= 345.72/ [2256 + (4.186 x 11)]
= 0.15 kg
= 150 g
Two children are playing with a roll of paper towels. One child holds the roll between the index fingers of her hands so that it is free to rotate, and the second child pulls at constant speed on the free end of the paper towels. As the child pulls the paper towels, the radius of the roll of remaining towels decreases.
a)How does the torque on the roll change with time?
increases
decreases
stays the same
b)How does the angular speed of the roll change in time?
increases
decreases
stays the same
Answer:
a )Decreases
b ) Increases
c.) It's likely to break
Explanation:
a )The torque is as a result of friction, and also the magnitude is dependent on the normal force that exist between the surface in contact. The torque decrease because there is decrease in frictional force as the weight of the roll decrease
b.)The angular velocity will increase as radius o f the roll decrease because it is operating at constant speed.
c)if the child suddenly hit the roll, the papper will break, because it's angular acceleration might not be able to move along with the papper. Situation like this occur when there is large radius
The average bulk resistivity of the human body (apart from surface resistance of the skin) is about 5.0 Ω⋅m. The conducting path between the hands can be represented approximately as a cylinder 1.6 m long and 0.10 m in diameter. The skin resistance can be made negligible by soaking the hands in salt water (a) What is the resistance between the hands if the skin resistance is negligible? (b) if skin resistance is negligible, what potential difference between the hands is needed for lethal shock current 100 mA?
Answer:
A) R = 1019.11 Ω
B) V = 101.91 V
Explanation:
a) The resistance is given by the formula;
R = ρL/A
Where;
ρ is bulk density = 5.0 Ωm
L is length of cylinder = 1.6m
A is area = (π/4)D² = (π/4) x 0.1² = 0.007854 m²
Plugging in the relevant values, we obtain ;
R = (5 Ωm x 1.6m)/(0.007854 m²)
R = 1019.11 Ω
b) potential difference is given by;
V = RI
Thus, plugging in relevant values, we obtain;
V = 1019.11 Ω ∙ 0.1A
V = 101.91 V
The resistance between the hands if the skin resistance is negligible is approximately [tex]\( 1019 \, \Omega \)[/tex], the potential difference between the hands needed for a lethal shock current of 100 mA is approximately [tex]\( 101.9 \, \text{V} \).[/tex]
To solve this problem, we'll use the formulas for resistivity and Ohm's law.
Part (a): Resistance Between the Hands
The resistance R of a cylindrical conductor can be calculated using the formula:
[tex]\[ R = \rho \frac{L}{A} \][/tex]
where:
- [tex]\( \rho \)[/tex] is the resistivity of the material (in this case, the human body's resistivity is [tex](\( 5.0 \, \Omega \cdot \text{m} \))[/tex].
- L is the length of the conductor (1.6 m).
- A is the cross-sectional area of the conductor.
First, we need to calculate the cross-sectional area A of the cylindrical conductor. The cross-sectional area of a cylinder is given by:
[tex]\[ A = \pi \left(\frac{d}{2}\right)^2 \][/tex]
where d is the diameter of the cylinder. Here, [tex]\( d = 0.10 \, \text{m} \)[/tex].
So,
[tex]\[ A = \pi \left(\frac{0.10 \, \text{m}}{2}\right)^2 = \pi \left(0.05 \, \text{m}\right)^2 \]\[ A = \pi \cdot (0.05)^2 \, \text{m}^2 \]\[ A \approx 3.14 \cdot 0.0025 \, \text{m}^2 \]\[ A \approx 0.00785 \, \text{m}^2 \][/tex]
Now we can calculate the resistance R:
[tex]\[ R = 5.0 \, \Omega \cdot \text{m} \frac{1.6 \, \text{m}}{0.00785 \, \text{m}^2} \]\[ R = 5.0 \cdot \frac{1.6}{0.00785} \, \Omega \]\[ R = 5.0 \cdot 203.82 \, \Omega \]\[ R \approx 1019.1 \, \Omega \][/tex]
Part (b): Potential Difference for Lethal Shock Current
Ohm's law states that the voltage V across a resistor is given by:
[tex]\[ V = I \cdot R \][/tex]
where I is the current and R is the resistance.
Given that the lethal shock current is [tex]\( 100 \, \text{mA} = 0.1 \, \text{A} \)[/tex] and the resistance [tex]\( R \) is \( 1019 \, \Omega \)[/tex]:
[tex]\[ V = 0.1 \, \text{A} \cdot 1019 \, \Omega \]\[ V = 101.9 \, \text{V} \][/tex]
Suppose you are planning a trip in which a spacecraft is to travel at a constant velocity for exactly six months, as measured by a clock on board the spacecraft, and then return home at the same speed. Upon return, the people on earth will have advanced exactly 110 years into the future. According to special relativity, how fast must you travel
Answer:
0.999958c
Explanation:
Remember that the trip involves traveling for six months at a constant velocity thus returning home at same speed . The time interval of this trip will therefore be one year.
Accurate time interval to be measured by the clock on the spaceship Δt0 = 1.0 years
Time interval as advanced on earth observed from the spacecraft Δt = 110 years
the formula for time dilation is
Δt = Δt0 /√(1-v2/c2)
or v = c*√1-(Δt0/Δt)2
=c*√[1-(1year/110years)2]
= 0.999958c
Consider a perfectly reflecting mirror oriented so that solar radiation of intensity I is incident upon, and perpendicular to, the reflective surface of the mirror.
(a) If the mirror has surface area A, what is Frad, the magnitude of the average force due to the radiation pressure of the sunlight on the mirror?
Express your answer in terms of the intensity I, the mirror's surface area A, and the speed of light c.
Answer:
Frad = 2IA/C
Explanation:
see attached file
A very long uniform line of charge has charge per unit length λ1 = 4.80 μC/m and lies along the x-axis. A second long uniform line of charge has charge per unit length λ2 = -2.26 μC/m and is parallel to the x-axis at y1 = 0.400 m . (Hint: You will need to know or derive using Gauss law the electric field by a uniform line charge)
Answer:
a) E=228391.8 N/C
b) E=-59345.91N/C
Explanation:
You can use Gauss law to find the net electric field produced by both line of charges.
[tex]\int \vec{E_1}\cdot d\vec{r}=\frac{\lambda_1}{\epsilon_o}\\\\E_1(2\pi r)=\frac{\lambda_1}{\epsilon_o}\\\\E_1=\frac{\lambda_1}{2\pi \epsilon_o r_1}\\\\\int \vec{E_2}\cdot d\vec{r}=\frac{\lambda_2}{\epsilon_o}\\\\E_2=\frac{\lambda_2}{2\pi \epsilon_o r_2}[/tex]
Where E1 and E2 are the electric field generated at a distance of r1 and r2 respectively from the line of charges.
The net electric field at point r will be:
[tex]E=E_1+E_2=\frac{1}{2\pi \epsilon_o}(\frac{\lambda_1}{r_1}+\frac{\lambda_2}{r_2})[/tex]
a) for y=0.200m, r1=0.200m and r2=0.200m:
[tex]E=\frac{1}{2\pi(8.85*10^{-12}C^2/Nm^2)}[\frac{4.80*10^{-6}C}{0.200m}-\frac{2.26*10^{-6}C}{0.200m}}]=228391.8N/C[/tex]
b) for y=0.600m, r1=0.600m, r2=0.200m:
[tex]E=\frac{1}{2\pi(8.85*10^{-12}C^2/Nm^2)}[\frac{4.80*10^{-6}C}{0.600m}-\frac{2.26*10^{-6}C}{0.200m}}]=-59345.91N/C[/tex]
a) The electric field strength for case 1 will be 228391.8 N/C
b) The electric field strength for case 2 will be 59345.91 N/C
What is gauss law?The total electric flux out of a closed surface is equal to the charge contained divided by the permittivity,
According to Gauss Law. The electric flux in a given area is calculated by multiplying the electric field by the area of the surface projected in a plane perpendicular to the field.
The given data in the problem is;
λ₁ is the charge per unit length for charge 1 = 4.80 μC/m
λ₂ is the charge per unit length for charge 2 =-2.26 μC/m
y₁ is the distance from charge 1 =0.400 m.
From the gauss law, the net electric field is produced by both lines of charges will be .;
[tex]\rm E= \frac{\lambda_}{2 \pi \epsilon_0 r_2} \\\\ \rm E_1= \frac{\lambda_1}{2 \pi \epsilon_0 r_1} \\\\ \rm E_2= \frac{\lambda_2}{2 \pi \epsilon_0 r_2}[/tex]
The total electric field will be the sum of the electric field for the charge 1 and2;
[tex]\rm E=E_1+E_2 \\\\ \rm E=\frac{\lambda_1}{2 \pi \epsilon_0 r_1}+\frac{\lambda_2}{2 \pi \epsilon_0 r_2} \\\\[/tex]
The net electric field for y=0.200m, r₁=0.200m, and r₂=0.200 m will be;
[tex]\rm E=\frac{4.80 \times 10^{-6}}{2 \times 3.14 8.85 \times 10^{-12} \times 0.200}-\frac{2.26 \times 10^{-6}}{2 \times 3.14 \times 8.85 \times 10^{-12}} \\\\\rm E=228391.8 \ N/C[/tex]
The net electric field for y=0.600m, r₁=0.600m, r₂=0.200 m will be;
[tex]\rm E=\frac{4.80 \times 10^{-6}}{2 \times 3.14 8.85 \times 10^{-12} \times 0.600}-\frac{2.26 \times 10^{-6}}{2 \times 3.14 \times 8.85 \times 10^{-12}} \\\\\rm E=-59345.51 \ N/C[/tex]
Hence the electric field strength for case 1 and case 2 will be 228391.8 N/C and 59345.91 N/C respectively.
To learn more about the gauss law refer to the link;
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A 56.0-kg child takes a ride on a Ferris wheel that rotates four times each minute and has a diameter of 22.0 m. (a) What is the centripetal acceleration of the child? magnitude 1.76 m/s2 direction (b) What force (magnitude and direction) does the seat exert on the child at the lowest point of the ride? magnitude 647.4 N direction (c) What force does the seat exert on the child at the highest point of the ride? magnitude 450.2 N direction (d) What force does the seat exert on the child when the child is halfway between the top and bottom? (Assume the Ferris wheel is rotating clockwise and the child is moving upward.) magnitude N direction 79.8 ° counter-clockwise from the horizontal
Answer:
a. 3.86 m/s²
b. 332.64 N directed upwards towards the center of the ferris wheel.
c. 764.96 N directed downwards towards the center of the ferris wheel.
d. 589.84 N at 21.5° counterclockwise from the horizontal direction.
Explanation:
a. Since the ferris wheel rotates 4 times per minute, its period, T = 60 s/4 = 15 s.
We now find it angular speed ω = 2π/T = 2π/15 = 0.418 rad/s
We then calculate its centripetal acceleration from a = rω² where r = radius of ferris wheel = 22.0 m.
So, a = 22 m × (0.418 rad/s)² = 3.86 m/s²
b. At the lowest point, the normal force, N and the centripetal force, F both act in opposite directions to the weight, mg of the object. So,
N + F = mg
N = mg - F
N = mg - ma where a is the centripetal acceleration
N = m(g - a)
N = 56 kg(9.8 m/s² - 3.86 m/s²)
N = 56 kg × 5.94 m/s²
N = 332.64 m/s²
The normal force the seat exerts on the child is thus 332.64 N directed upwards towards the center of the ferris wheel.
c. At the highest point, the weight, mg of the object and the centripetal force, F both act in opposite directions to the normal force, N. So,
N = mg + F
N = mg + ma where a is the centripetal acceleration
N = m(g + a)
N = 56 kg(9.8 m/s² + 3.86 m/s²)
N = 56 kg × 13.66 m/s²
N = 764.96 N
The normal force the seat exerts on the child is thus 764.96 N directed downwards towards the center of the ferris wheel.
d. Half way between the top and the bottom of the ferris wheel, the normal force must balance the weight and the centripetal force so the child doesn't fall off. For this to happen, the normal force is thus the resultanf of the centripetal force and the weight of the child. Since these two forces are perpendicular at this instance,
N = √[(mg)² + (ma)²] = m√(g² + a²) = 56 kg√[(9.8 m/s²)² + (3.86 m/s²)²] = 56 kg√[(97.196 (m/s²)² + 14.8996(m/s²)²] = 56kg√110.9396 (m/s²)² = 56 kg × 10.53 m/s² = 589.84 N.
Since the centripetal force acts towards the center of the ferris wheel in the horizontal direction, it is equal to the horizontal component of the normal force, Also, the weight acts downwards and is equal to the vertical component of the normal force.
So, the direction of the normal force is gotten from
tanθ = ma/mg = a/g
θ = tan⁻¹(a/g) = tan⁻¹(3.86 m/s² / -9.8 m/s²) = tan⁻¹(-0.3939) = -21.5°. Since the angle is it shows a counter clockwise direction.
So, the normal force is 589.84 N at 21.5° counterclockwise from the horizontal direction.
(a) The centripetal acceleration of the child is 1.94 m/s².
(b) The force the seat exert on the child at the lowest point of the ride is 657.4 N.
(c) The force the seat exert on the child at the highest point of the ride is 440.2 N.
(d) The force the seat exert on the child when the child is halfway between the top and bottom is 108.64 N.
The given parameters;
mass of the child, m = 56 kgangular speed, ω = 4 rev/mindiameter of the wheel, d = 22 mradius of the wheel, r = 11 mThe centripetal acceleration of the child is calculated as follows;
[tex]a_c = \omega ^2 r\\\\[/tex]
where;
ω is angular speed of the wheel in rad/s
The angular speed of the wheel in rad/s is calculated as follows;
[tex]\omega = 4 \ \frac{rev}{\min} \times \frac{2\pi \ rad}{1 \ rev} \times \frac{1\min}{60 \ s} \\\\\omega = 0.419 \ rad/s[/tex]
The centripetal acceleration of the child is calculated as;
[tex]a_c = \omega^2 r\\\\a_c = (0.419)^2 \times 11\\\\a_c = 1.94 \ m/s^2[/tex]
The force the seat exert on the child at the lowest point of the ride is calculated as;
[tex]T_{bottom} = ma_c + mg\\\\T_{bottom} = m(a_c + g)\\\\T_{bottom} = 56(1.94 + 9.8)\\\\T_{bottom} = 657.4 \ N[/tex]
The force the seat exert on the child at the highest point of the ride is calculated as;
[tex]T_{top} = mg- ma_c\\\\T_{top} = m(g - a_c)\\\\T_{top} = 56(9.8 - 1.94)\\\\T_{top} = 440.2 \ N[/tex]
The force the seat exert on the child when the child is halfway between the top and bottom;
[tex]T = ma_c\\\\T = 56(1.94)\\\\T = 108.64 \ N[/tex]
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A hemispherical droplet of liquid water, lying on a flat surface, evaporates by molecular diffusion through still air surrounding the droplet. The droplet initially has a radius R. As the liquid water slowly evaporates, the droplet shrinks slowly with time, but the flux of the water vapor is at a nominal steady state. The temperature of the droplet and the surrounding still air are kept constant. The air contains water vapor of fixed concentration at an infinitely long distance from the droplet’s surface. After drawing a picture of the physical process, select a coordinate system that will best describe this diffusion process, list at least five reasonable assumptions for the mass-transfer aspects of the water-evaporation process, and simplify the general differential equation for mass transfer in terms of the flux NA. Finally, specify the simplified differential form of Fick’s flux equation for water vapor (species A), and propose reasonable boundary conditions.
Answer:
Explanation:
question answered below
We described the diffusion process of a slowly evaporating hemispherical water droplet by adopting a spherical coordinate system. We made five assumptions: steady-state conditions, isotropic medium, uniform temperature, constant concentration of water vapor in the surrounding air, and no bulk motion of air. The differential form of Fick's law was derived, and two boundary conditions regarding the concentration of water were proposed.
Explanation:To answer your question regarding the diffusion process of a hemispherical droplet of water slowly evaporating on a flat surface, we will start by selecting a spherical coordinate system. This is chosen because a spherical system best represents a hemispherical droplet with a shrinking radius R.
Now, let's list at least five reasonable assumptions for the mass-transfer aspects of the water-evaporation process:
Steady-state conditions - The rate of evaporation is constant over time.Isotropic medium - The properties of the medium (air) are the same in all directions.Uniform temperature - The temperature of the system is constant throughout the process.Constant concentration of water vapor - At an infinite distance from the droplet surface, the air contains a fixed concentration of water vapor.No bulk motion of air - The air around the droplet is still, causing diffusion to occur solely due to molecular motion.To express the mass transfer in terms of the flux NA, we need to derive from Fick's first law, which states that the molar flux due to diffusion is proportional to the concentration gradient. In this case, it simplifies to: NA = -D(dCA/dx), where D is the diffusion coefficient and dCA/dx is the concentration gradient of species A (water).
As for the boundary conditions, we can consider two conditions:
The concentration of water at the droplet's surface is the saturation concentration.The concentration at infinite distance from the droplet is essentially constant.Learn more about Diffusion of Evaporating Water Droplet here:https://brainly.com/question/33422701
#SPJ3
A person stands in an elevator
weighing a Cheeseburger with a
kitchen scale « lit could happent
The mass of the cheese burger at
10 ilsoka The scale reads l-ION
Determine the magnitude ana
Lirecteon of the netforce on the
Cheeseburger
Answer:
Noennt ied olod l qeu es ocmo a balazuna de cozcna
in
Explanation:
Explicitly solve the Heisenberg equations of motion to find the time–dependent raising and lowering (creation and annihilation) operators for a one-dimensional oscillator in the Heisenberg picture. Show these operators are consistent with the time–dependent position and momentum operators previously derived in Lecture
Answer:
see detailed solution attached.
Explanation:
Final answer:
In the Heisenberg picture of quantum mechanics, the creation and annihilation operators for a one-dimensional harmonic oscillator evolve in time as â(t) = â(0)e-iwt and â¹(t) = â¹(0)eiwt, respectively, which are consistent with the time evolution of the position and momentum operators derived from the Heisenberg equations of motion.
Explanation:
Time-Dependent Creation and Annihilation Operators
In the Heisenberg picture of quantum mechanics, unlike the Schrödinger picture, the state vectors are stationary and the operators evolve with time. For the one-dimensional harmonic oscillator, the time-dependent creation (â¹(t)) and annihilation (â(t)) operators can be solved explicitly. The Heisenberg equations of motion for these operators are given by:
â(t)= â(0)e-iwt
â¹(t) = â¹(0)eiwt
where â(0) and â¹(0) are the initial operators at t=0, and w is the angular frequency of the oscillator. These time-dependent operators are then consistent with the previously derived time-dependent position (q(t)) and momentum (p(t)) operators:
q(t) = q(0)cos(wt) + (p(0)/mw)sin(wt)
p(t) = p(0)cos(wt) - mwq(0)sin(wt)
Here, m is the mass of the oscillator, and w is again the angular frequency. This consistency is because the position and momentum operators can be expressed in terms of the creation and annihilation operators. The expressions for â(t) and â¹(t) in the Heisenberg equations demonstrate that these operators oscillate with time in a manner that corresponds to the harmonic nature of the oscillator's motion in quantum mechanics.
The time evolution of any quantum mechanical operator in the Heisenberg picture can be described by the time evolution operator, U, which is unitary. This allows time propagation of operators while keeping the wavefunction unchanged.
We will use a video to analyze the dependence of the magnitude of the Coulomb force between two electrically-charged spheres on the distance between the centers of the spheres. The electrical interaction is one of the fundamental forces of nature and acts between any pair of charged objects, therefore it is important to understand how precisely the separation distance affects the corresponding force between them.
1. Study conceptually the nature of Hint 1. Unit conversions Note that 1 nC 109 c. Hint2. The values for the first data point The first suggested data point was 31.9 cm and 0.00016 N electric charge and force
2. Take measurements of the force exerted between two electrically- charged spheres as the distance between them is varied
3. Determine graphically the relationship between electric force and distance nc
Find the attached photo for the solution
A 3.0-µF capacitor charged to 40 V and a 5.0-µF capacitor charged to 18 V are connected to each other, with the positive plate of each connected to the negative plate of the other. What is the final charge on the 3.0-µF capacitor?
The final charge on the 3.0-µF capacitor is 90 µC.
Explanation:To find the final charge on the 3.0-µF capacitor, we need to use the concept of charge conservation in a series circuit. In a series circuit, the charge across capacitors connected in series is the same. Therefore, the final charge on the 3.0-µF capacitor will be the same as the charge on the 5.0-µF capacitor.
Using the formula Q = CV, where Q is the charge, C is the capacitance, and V is the voltage, we can calculate the charge on the 5.0-µF capacitor.
Q = (5.0 µF)(18 V) = 90 µC.
Therefore, the final charge on the 3.0-µF capacitor is also 90 µC.
A new concrete mix is being designed to provide adequate compressive strength for concrete blocks. The specification for a particular application calls for the blocks to have a mean compressive strength µ greater than 1350 kPa. A sample of 100 blocks is produced and tested. Their mean compressive strength is 1356 kPa and their standard deviation is 70 kP
Complete question:
new concrete mix is being designed to provide adequate compressive strength for concrete blocks. The specification for a particular application calls for the blocks to have a mean compressive strength µ greater than 1350 kPa. A sample of 100 blocks is produced and tested. Their mean compressive strength is 1356 kPa and their standard deviation is 70 kP
a) Find the p value.
b) Do you believe it is plausible that the blocks do not meet the specification, or are you convinced that they do? Expain your reasoning.
Answer:
a) p-value= 0.1949
b) It is possible the blocks do not meet the specifications
Explanation:
Given:
n = 100
Sample mean, X' = 1356
Standard deviation, s.d = 70
a) To find p- value.
Null hypothesis:
H0: u ≤ 1350
Alternative hypothesis:
H1 : u > 1350
The test statistic wll be:
[tex] z= \frac{X'-u_o}{s.d/ \sqrt{n}}[/tex]
[tex] = \frac{1356-1350}{70/\sqrt{100}}[/tex]
=0.86
The p value will be:
= P(z>0.86)
= 1-P(z≤0.86)
Using the normal distribution table, we now have:
1 - 0.8051
= 0.1949
P value = 0.1949
b) Since our p-value is 0.1949, we do not reject the null hypothesis, because the p-value, 0.1949, is not small. This means that it is possible the blocks do not meet the specifications.
The probability that the compressive strength is greater than 1350 kPa is 80.51%
Z score is used to determine by how many standard deviations the raw score is above or below the mean. The z score is given by:
[tex]z=\frac{x-\mu}{\sigma/\sqrt{n} } \\\\Where\ x=raw\ score,\mu=mean, \sigma=standard\ deviation, n=sample\ size[/tex]
Given that n = 100, μ = 1356, σ = 70. For x > 1350 kPa:
[tex]z=\frac{1350-1356}{70/\sqrt{100} } =-0.86[/tex]
From the normal distribution table, P(x > 1350) = P(z > -0.86) = 1 - P(z < -0.86) = 1 - 0.1949 = 80.51%
Hence the probability that the compressive strength is greater than 1350 kPa is 80.51%
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The index of refraction of silicate flint glass for red light is 1.620 and for violet light is 1.660 . A beam of white light in this glass strikes the glass–air interface at a 25.50∘ angle of incidence and refracts out into the air. What is the angular separation between the red and violet components of the spectrum that emerges from the glass?
Answer:
10.16 degrees
Explanation:
Apply Snells Law for both wavelenghts
\(n_{1}sin\theta_{1} = n_{2}sin\theta_{2}\)
For red
(1.620)(sin 25.5) = (1)(sin r)
For red, the angle is 35.45degrees
For violet
(1.660)(sin 25.5) = (1)(sin v)
For violet, the angle is 45.6 degrees
The difference is 45.6- 35.45 = 10.16 degrees
the cart. The coefficient of kinetic friction between the person and the cart is 0.480. Friction between the cart and ground can be ignored. (Let the positive direction be to the right.) (a) Find the final velocity of the person and cart relative to the ground. (Indicate the direction with the sign of your answer.) m/s (b) Find the frictional force acting on the person while he is sliding across the top surface of the cart. (Indicate the direction with the sign of your answer.) N (c) How long does the frictional force act on the person? s (d) Find the change in momentum of the person. (Indicate the direction with the sign of your answer.) N · s Find the change in momentum of the cart. (Indicate the direction with the sign of your answer.) N · s (e) Determine the displacement of the person relative to the ground while he is sliding on the cart. (Indicate the direction with the sign of your answer.) m (f) Determine the displacement of the cart relative to the ground while the person is sliding. (Indicate the direction with the sign of your answer.) m (g) Find the change in kinetic energy of the person. J (h) Find the change in kinetic energy of the cart. J (i) Explain why the answers to (g) and (h) differ. (What kind of collision is this one, and what accounts for the loss of mechanical energy?)
Answer:
(a) Find the final velocity of the person and cart relative to the ground. = 1.367m/s
(b) Find the frictional force acting on the person while he is sliding across the top surface of the cart = 286.944N
(c) How long does the frictional force act on the person? = 0.5809s
(d) Find the change in momentum of the person. = 166.774N
(e) Determine the displacement of the person relative to the ground while he is sliding on the cart. = 1.5878m
(f) Determine the displacement of the cart relative to the ground while the person is sliding. = 0.3970m
(g) Find the change in kinetic energy of the person. = -455.71J
(h) Find the change in kinetic energy of the cart = 113.99j
(i) Explain why the answers to (g) and (h) differ.
the force exerted on the cart by the person must be equal in magnitude and opposite in direction to the force exerted on the cart by the person. The changes in momentum of the two cart must be equal in magnitude and must add up to zero. The following represents two way thinking about "WAY". The distance the cart moves is different from the distance moved by the point of application of frictional force on the cart.
Explanation:
check attachment for explanation.
The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According to one set of experiments, the average area of the Achilles tendon is 78.2 mm^2 , its average length is 26 cm , and its average Young's modulus is 1474 MPa . How much tensile stress is required to stretch this muscle by 5.2% of its length? If we model the tendon as a spring, what is its force constant? If a 75 kg sprinter exerts a force of 13.0 times his weight on his Achilles tendon, by how much will it stretch?
Answer:
1) tensile stress = 76.648 Mpa
2) extension = 0.0215 m
Explanation:
Detailed explanation and calculation is shown in the image below
Final answer:
Tensile stress and the force constant for the Achilles tendon can be calculated using Young's modulus, Hooke's Law, and the given dimensions. A 75 kg sprinter exerting a force 13 times his weight would cause a specific amount of stretch in the tendon, calculated by applying Hooke's Law with the determined spring constant.
Explanation:
The tensile stress required to stretch the Achilles tendon by 5.2% of its length can be calculated using Hooke's Law and the definition of stress and strain. Stress (σ) is the force applied per unit area (A) and strain (ε) is the relative change in length (ΔL/L). The Young's modulus (E) relates stress and strain through σ = Eε.
First, calculate the strain which is 5.2% or 0.052. Since the Young's modulus (E) is given as 1474 MPa and the strain (ε) is 0.052, we can now calculate the stress:
σ = Eε = 1474 MPa × 0.052 = 76.648 MPa
Next, we model the tendon as a spring to find the force constant (k). Hooke's Law states that F = kΔx, where F is the force applied and Δx is the change in length. To find k, we rearrange the formula to k = F/Δx. Here, F is the tensile force, which is σ × A. We substitute the stress we found and the area of the tendon to find k.
For a 75 kg sprinter exerting a force of 13.0 times his weight, the force F would be 13.0 × 75 kg × 9.8 m/s² (acceleration due to gravity). To find the stretch (Δx), we use Hooke's Law again with the calculated force constant k.
The Achilles tendon will stretch according to that force, proportionally to the spring constant k. The exact calculations require substitution of the calculated force into the Hooke's Law equation to solve for Δx.
A pendulum string with the length of 105 cm has the 325 g bob attached to it. At the lowest point of the swing the pendulum bob moves with the speed of 2.15 m/s. Determine: a) the centripetal acceleration of the pendulum bob at this point; b) the force of tension in the string at this point; c) the kinetic energy of the pendulum bob at this point;
Answer:
A. 4.40m/s²
B. 4.615N
C. 0.7511J
Explanation:
A. Ac= V²/L
= (2.15)²/1.05
= 4.50m/s²
B. T =Mv²/L + mg
0.325(4.40)+ 0.325(9.8)
= 4.615N
C. K.E = 1/2mv²
=0.7511J
You can also refer to attached handwritten document for more details
Answer:
(a) 4.4 m/s²
(b) 4.615 N.
(c) 0.751 J
Explanation:
(a)
Using,
a' = v²/r..................... Equation 1
Where a' = centripetal acceleration, v = speed of the pendulum bob, r = radius or length of the pendulum bob.
Given: v = 2.15 m/s, r = 105 cm = 1.05 m
Substitute into equation 1
a' = 2.15²/1.05
a' = 4.4 m/s².
(b) The force of tension in the string = Tangential force + weight of the bob.
T = ma'+mg..................... Equation 2
Where T = Force of tension in the string, m = mass of the bob, g = acceleration due to gravity.
Given: m = 325 g = 0.325 kg, a' = 4.4 m/s², g = 9.8 m/s²
Substitute into equation 2
T = 0.325×4.4+0.3325×9.8
T = 1.43+3.185
T = 4.615 N.
(c) Kinetic energy of he bob at that point = 1/2mv²
Ek = 1/2mv²...................... Equation 3
Where Ek = kinetic energy of the bob
Given: m = 0.325 kg, v = 2.15 m/s
Substitute into equation 3
Ek = 1/2(0.325)(2.15²)
Ek = 0.751 J