Answer:
t = 025 s
Explanation:
We know
weight, W = 4 pounds
spring constant, k = 2 lb/ft
Positive damping, β = 1
Therefore mass, m = W / g
m = 4 / 32
= 1 / 8 slug
From Newtons 2nd law
[tex]\frac{d^{2}x}{dt^{2}}=-kx-\beta .\frac{dx}{dt}[/tex]
where x(t) is the displacement from the mean or equilibrium position. The equation can be written as
[tex]\frac{d^{2}x}{dt^{2}}+\frac{\beta }{m}.\frac{dx}{dt}+\frac{k}{m}x=0[/tex]
Substituting the values, the DE becomes
[tex]\frac{d^{2}x}{dt^{2}}+8\frac{dx}{dt}+16x=0[/tex]
Now the equation is
[tex]m^{2}+8m+16=0[/tex]
and on solving the roots are
[tex]m_{1}[/tex] = [tex]m_{2}[/tex] = -4
Therefore the general solution is [tex]x(t)=e^{-4t}\left ( c_{1}+c_{2}t \right )[/tex]
Now for initial condition x(0) = -1 ft
x'(0)= 8 ft/s
Now we can find the equation of motion becomes,
[tex]x(t)=e^{-4t}\left ( -1+4t \right )[/tex]
Therefore, the mass passes through the equilibrium when
x(t) = 0
[tex]e^{-4t}\left ( -1+4t \right )[/tex] = 0
-1+4t = 0
t = [tex]\frac{1}{4}[/tex]
= 0.25 s
If the magnitude of the electric field in air exceeds roughly 3 ✕ 106 N/C, the air breaks down and a spark forms. For a two-disk capacitor of radius 54 cm with a gap of 3 mm, what is the maximum charge (plus and minus) that can be placed on the disks without a spark forming (which would permit charge to flow from one disk to the other)? The constant ε0 = 8.85 ✕ 10-12 C2/(N·m2).
The electric field inside a parallel plate capacitor is given by:
E = Q/(ε₀A)
E is the electric field, Q is the charge stored on one of the plates, and A is the area of one of the plates.
The plates are circular, so the area A of one of the plates is given by:
A = πr²
where r is the radius.
Therefore the electric field is given by:
E = Q/(ε₀πr²)
Given values:
E = 3×10⁶N/C (max E field allowed before breakdown occurs)
r = 54×10⁻²m
Plug in these values and solve for Q:
3×10⁶ = Q/(ε₀π(54×10⁻²)²)
Q = 2.4×10⁻⁵C
Ideal meters problem. What internal resistance is ideal for a voltmeter? What internal resistance is ideal for an ammeter?
Answer:
Answer to the question:
Explanation:
The value of the internal resistance of an ideal voltmeter is infinite.
The value of the internal resistance of an ideal ammeter is zero.
Final answer:
The ideal internal resistance for a voltmeter is very high to avoid affecting the circuit during voltage measurements, while for an ammeter it should be very low to avoid affecting current measurements. Incorrect use of meters can lead to inaccurate readings and potential damage.
Explanation:
Ideal Internal Resistance of Meters:
When it comes to the ideal internal resistance of a voltmeter, it should be as high as possible. This is because a voltmeter is used in parallel with a component to measure its voltage. If the voltmeter has a high internal resistance, it will minimize the current flowing through the voltmeter, thereby causing minimal change in the overall circuit operation. For example, a digital voltmeter can have an internal resistance in the megaohms (MΩ), which is ideal for not affecting the circuit.
On the other hand, the ideal internal resistance of an ammeter is very low. An ammeter is connected in series with a circuit to measure the current flowing through it. Thus, to prevent it from significantly altering the voltage drop across the circuit or the current itself, an ammeter should have minimal resistance. Digital ammeters can have much lower internal resistance compared to analog meters, making them less intrusive in circuit measurements.
If a meter with the wrong internal resistance is used, it could cause incorrect readings and potentially damage the meter or the circuit. For instance, using a meter in ammeter mode to measure voltage can short circuit the meter, as an ammeter's low resistance is not meant to handle the high potential differences associated with voltage measurements.
How are positive and negative ions formed
Answer: Ions are formed when atoms from group 1/3/2/17 gains or loses a small number of electrons.
Explanation: Let's take Na(Sodium) and Cl(chlorine), their atomic number are consecutively 11 and 17. Sodium's closest noble element is Neon(10) and Cl's is Argon(18). Now all atoms want to gain stability like the noble gases, they want their outer shell to be filled so that they don't have to wander around with other atoms. So to have stability Na will lose one of its electrons and Cl will take in one. Thus they consecutively will become plus charged and minus charged as the balance between their proton and electron numbers are gone
An ion is formed when a neutral atom gains or loses an electron.
A neutral atom has the same number of protons (+) and electrons (-).
If it gains another electron, it has too many negative charges, so it's a negative ion.
If it loses an electron, it has too many positive charges, so it's a positive ion.
=================================
What if it gains or loses a proton ?
That's a great question. I'm glad you asked.
Under normal circumstances, this hardly ever happens. But if it did ...
- If it somehow lost a proton from its nucleus, first of all, it would change the number of protons in the nucleus, so the atom would immediately become an atom of a different element.
- If it didn't lose an electron at the same time, then it would have too many electrons for the number of protons in the nucleus, so it would be a negative ion of the new element.
- If it somehow added a proton to its nucleus, it would change the number of protons in the nucleus, so the atom would become an atom of a different element. If it didn't add another electron at the same time, then it would have too few electrons for the number of protons in the nucleus, so it would be a positive ion of the new element.
Nuclear energy comes from splitting atoms of __________ to generate heat.
Answer:
Nuclear energy originates from the splitting of uranium atoms – a process called fission. This generates heat to produce steam, which is used by a turbine generator to generate electricity. Because nuclear power plants do not burn fuel, they do not produce greenhouse gas emissions.
Explanation:
Nuclear energy primarily comes from the process of nuclear fission, specifically the splitting of Uranium-235 atoms. This process releases immense energy which is utilized to generate power in nuclear power plants.
Explanation:Nuclear energy, used feasible in power plants, comes primarily from the process of splitting atoms of Uranium-235, a process known as nuclear fission. In this process, a neutron collides with a Uranium atom, causing the atom to split and release more neutrons along with a large amount of energy. This energy, in the form of heat, is then used to produce steam which drives turbines, thereby generating electricity.
Thus, it's clear that the process of splitting large, complex atomic nuclei, particularly those of Uranium-235, not only induces a chain reaction (due to the release of more neutrons) but also provides us with a sophisticated method of generating power in the form of nuclear energy.
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What is the relationship between air pressure and wind velocity
Marina is staring at an optical illusion where he sees a version of the American flag that is colored green, yellow, and black. When the flag is removed and she stares at a blank screen, she sees an afterimage of the flag that is red, white, and blue. Which theory best explains this illusion?
Explanation:
The reason why Marina sees the colour red, white and blue or the original colour of the American flag is that because of a phenomenon known as Afterimage. The retina in our eyes have mainly three receptors that are colour sensitive known as cones. These receptors can perceive the colour green, red and blue. Now when we look or stare at a particular colour for a long time, what happen is that our retina becomes tired and they ignore the colours that stared at. And now they work to form other colours at the retina just like the way when we produce other colour from the primary colour.
If the red receptor gets exhausted we will see the colour red. Likewise when we see the colour orange when we stare at the colour blue.
This explains the optical illusion of the American flag.
Final answer:
Marina's observation of a red, white, and blue afterimage after staring at a green, yellow, and black flag is explained by the opponent-process theory of color perception. This theory indicates that colors are perceived in opposing pairs, and overstimulation of certain color-sensitive cells can lead to the perception of their opposite colors when looking away.
Explanation:
The Opponent-Process Theory of Color Perception
The optical illusion experienced by Marina where she sees an afterimage of the American flag in red, white, and blue after staring at a flag colored green, yellow, and black can be explained by the opponent-process theory of color perception.
This theory suggests that color perception is controlled by the activity of two opposing sets of colors: red versus green, and blue versus yellow, plus a black versus white system. When Marina stares at the green, yellow, and black flag, the respective ganglion cells in her retina which are associated with these colors become fatigued.
After looking away and viewing a blank screen, these cells reduce their activity, resulting in Marina's brain interpreting the lack of those colors as their opposites, which are red, white, and blue. This means that the afterimage is not just a random occurrence but rather a direct consequence of the way our visual system works to perceive colors.
The opponent-process theory is supported by how the retinal ganglion cells and the neurons in the visual cortex process color signals, as well as experimental demonstrations like staring at a flag and observing the afterimage that appears.
This illusion occurs because while staring at the flag, the green, black, and yellow sensitive ganglion cells become overstimulated and when the gaze is moved to a white background, the decreased stimulation is interpreted as their opponent colors. This effect persists until the ganglion cells return to their normal activity state, at which point the afterimage will fade away.
Roberto and Laura are studying across from each other at a wide table. Laura slides a 2.2 kg book
toward Roberto. If the net force acting on the book is 1.6 N to the right, what is the book's acceleration?
Explanation:
Force = Mass × Acceleration
1.6 = 2.2 × a
a = 1.6/2.2
= 0.73 m/s^2
Note that the acceleration will be negative.
Answer: The acceleration of the book is [tex]0.73m/s^2[/tex]
Explanation:
Force is defined as the push or pull on an object with some mass that causes change in its velocity.
It is also defined as the mass multiplied by the acceleration of the object.
Mathematically,
[tex]F=ma[/tex]
where,
F = force exerted on the book = 1.6 N
m = mass of the book = 2.2 kg
a = acceleration of the book = ?
Putting values in above equation, we get:
[tex]1.6kg.m/s^2=2.2\times a\\\\a=\frac{1.6}{2.2}=0.73m/s^2[/tex]
Hence, the acceleration of the book is [tex]0.73m/s^2[/tex]
Two charged ping-pong balls separated by a distance of 1.63 m exert an electric force of 0.0224 N on each other. What will be the force if the objects are brought closer, to a separation of only 24.0 cm? (in N)
Answer: 1.024 N
Explanation:
Step 1:
Using Coulomb's law: F=kQ1Q2/d^2
We can rearrange the terms to get :
kQ1Q2=Fxr^2
Substituting: kQ1Q2=0.0224N x (1.63m)^2
Thus kQ1Q2=0.0595
We know that this value will not change when the balls are brought closer together.
Step 2:
Change from cm to m : 1cm=0.01m
24cm=0.24 m
Substitute into the new distance and the calculated value for kQ1Q2 into the coulomb law formula to calculate the new force
F=kQ1Q2/d^2=0.059/(0.24)^2
F=1.024N
Final answer:
The force between the ping-pong balls will be approximately 1.665 N when they are brought closer to a separation of 24.0 cm.
Explanation:
The force between two charged objects can be calculated using Coulomb's Law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
In this case, the initial force between the ping-pong balls is 0.0224 N when they are separated by 1.63 m. To find the force when they are brought closer to a separation of 24.0 cm, we can use the fact that the force is inversely proportional to the square of the distance.
We can set up a proportion:
(0.0224 N) / (1.63 m)²= (x) / (0.24 m)²
Solving for x, we find that the force will be approximately 1.665 N.
What is the resistance of a nichrome wire at 0.0 ∘c if its resistance is 120.00 ω at 11.5 ∘c?
Answer:
28.5 deg
Explanation:
The resistance of a nichrome wire at 0.0 ∘c if its resistance is 120.00 ω at 11.5 ∘c is 28.5 deg.
R = R0[1+ alpha(T-T0)]
R(28.5)=0.2000[1-0.005(28.5-0)]
The resistance of a nichrome is 28.5 deg.
How to find the resistance of a nichrome?The resistance of a nichrome wire at 0.0 ∘c if its resistance is 120.00 ω at 11.5 ∘c is 28.5 deg.
R = R0[1+ alpha(T-T0)]
R(28.5) = 0.2000[1-0.005(28.5-0)]
What's the value resistance of nichrome wire?Nichrome is continuously silvery-grey in shade, is corrosion-resistant, has an excessive melting thing of approximately 1, four hundred °C (2,550 °F), and has an electrical resistivity of around 112 microOhm-cm, that's around 66 times better resistivity than copper of one.678 microOhm-cm.
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A certain sound level increases by an additional 20 db. By how much does the intensity increase?
Answer:
The intensity increases by a factor 100.
Explanation:
Given that,
Sound intensity = 20 db
We need to calculate the intensity factor
[tex]F=10^{\dfrac{LI}{10}}[/tex]
Where, LI = sound intensity
Put the value into the formula
[tex]F=10^{\dfrac{20}{10}}[/tex]
[tex]F=10^2[/tex]
[tex]F=100[/tex]
Hence, The intensity increases by a factor 100.
Final answer:
A 20 dB increase in sound level corresponds to a 100 times increase in sound intensity, as each 10 dB increase represents a tenfold increase in intensity.
Explanation:
A sound level increase of 20 dB signifies a substantial increase in sound intensity. Given that each 10 dB increase corresponds to a tenfold increase in intensity, a 20 dB increase would mean the intensity is 10 times 10, or 100 times greater than the original level. This is derived from the logarithmic scale used to measure sound intensity in decibels (dB), where an increase of 10 dB represents a tenfold increase in sound intensity. Therefore, we can say that a 20 dB increase in sound level would result in the new sound being 100 times more intense than the original. To provide an example, if one sound measures 60 dB and another sound measures 80 dB, the latter is 100 times more intense than the former.
A tube 1.20 m long is closed at one end. A stretched wire is placed near the open end.The wire is 0.330 m long and has a mass of 9.60 g. It is fixed at both ends and oscillates in its fundamental mode.By resonance,it sets the air column in the tube into oscillation at that column’s fundamental frequency. Find (a) that frequency and (b) the tension in the wire.
Answer:
Explanation:
tube:
f=v/4L = 343/(4*1.2)= 71.4583Hz tube's fundamental frequency
wire:
f=v/2L -> v=2Lf
v= 2*0.323*71.4583= 46.162m/s
ρ= 0.0095/0.323= 0.02941kg/m
v=√(T/ρ) -> T=v^2*ρ
T= 46.162^2*0.02941= 62.67[N] Tension of wire.
The natural frequency of an object depends on its
Answer: composition, its size and shape.
Explanation:
All objects have a frequency that characterizes them, which is called natural frequency. This means that if a disturbance or vibration is emitted near the object, it will begin to vibrate due to its natural frequency.
It should be noted that there are objects that have more than one natural frequency, and this depends on the composition of the object, its elasticity, its shape and size.
The natural frequency of an object refers to the frequency at which it naturally tends to vibrate or oscillate when disturbed.
The specific factors that determine the natural frequency of an object are:
1. Mass: The mass of an object plays a significant role in determining its natural frequency.
2. Stiffness: The stiffness or rigidity of an object is another important factor in determining its natural frequency.
3. Geometry: The shape and size of an object also influence its natural frequency.
These factors interact with each other to determine the natural frequency of an object. Generally, objects with higher mass and/or higher stiffness will have lower natural frequencies, while objects with lower mass and/or lower stiffness will have higher natural frequencies.
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In a total-immersion measurement of a woman's density, she is found to have a mass of 63 kg in air and an apparent mass of 0.0975 kg when completely submerged with lungs almost totally empty.
A. What mass, in kg, of water does she displace?
B. What is her volume in m^3?
C. What is her average density in kg/m^3?
D. If her lung capacity is 1.75 L, is she able to float without treading water with her lungs filled with air? Assume the density of air is 1.29 kg/m3.
Answer:
Explanation:
A) mass of displaced water = loss of mass in water = 63 - .0975 = 62.9025 kg
B) her volume = volume of displaced water
= mass of displaced water / density of water = 62.9025 / 1000 m³.
= 62.9025 x 10⁻³ m³
C) her average density = her mass / her volume = 63 / 62.9025 x 10⁻³
= 1.00155 x 10³ kg / m³
D) lung capacity = 1.75 L = 1.75 x 10⁻³ m³
buoyant force created by air in the lungs = 1.75 x 10⁻³ ( 1000- 1.29 ) = 1.74 kg
As it is more than 0.0975 kg , the apparent weight in water so woman will float in water .
A. Mass of Water Displaced: ≈ 62.99 kg
B. Volume of Woman: ≈ 0.06299 m³
C. Average Density: ≈ 1000 kg/m³
D. Yes, she can float with lungs filled with air.
We can solve this problem using the concepts of buoyancy and density. Here's how to find the answers:
A. Mass of Water Displaced:
1. Buoyant Force: The difference between her mass in air and apparent mass underwater represents the buoyant force exerted by the water.
2. Buoyant Force = Weight in Air - Apparent Weight = (63 kg * 9.81 m/s²) - (0.0975 kg * 9.81 m/s²) (We can multiply mass by gravitational acceleration to convert it to weight, but for this problem, it cancels out)
3. Buoyant Force ≈ 618.27 N (Newtons)
Since buoyant force equals the weight of the water displaced, the mass of water displaced is:
Mass of Displaced Water = Buoyant Force / Gravitational Acceleration
Mass of Displaced Water ≈ 618.27 N / 9.81 m/s² ≈ 62.99 kg (rounded to two decimal places)
B. Volume of Woman:
1. Density of Water: We can assume the density of water to be 1000 kg/m³ (a standard value).
2. Volume of Displaced Water = Mass of Displaced Water / Density of Water
3. Volume ≈ 62.99 kg / 1000 kg/m³ ≈ 0.06299 m³ (rounded to five decimal places)
C. Average Density of Woman:
1. Woman's Volume (from part B): 0.06299 m³
2. Woman's Mass: 63 kg
3. Density = Mass / Volume
4. Average Density ≈ 63 kg / 0.06299 m³ ≈ 1000 kg/m³ (rounded to three decimal places)
D. Ability to Float:
1. Density of Air: 1.29 kg/m³
2. Volume of Air in Lungs: 1.75 L = 0.00175 m³ (convert liters to cubic meters)
3. When lungs are filled with air, her effective volume increases by the volume of air in her lungs.
4. Effective Volume with Air: 0.06299 m³ (woman's volume) + 0.00175 m³ (air in lungs) ≈ 0.06474 m³
5. When considering air in her lungs, her effective density becomes:
Effective Density = Mass / Effective Volume
Effective Density ≈ 63 kg / 0.06474 m³ ≈ 973.3 kg/m³ (rounded to one decimal place)
Since her effective density (with air in lungs) is lower than the density of water (1000 kg/m³), she would be able to float with her lungs filled with air.
Answers:
A. Mass of Water Displaced: ≈ 62.99 kg
B. Volume of Woman: ≈ 0.06299 m³
C. Average Density: ≈ 1000 kg/m³
D. Yes, she can float with lungs filled with air.
A 65-kg bungee jumper, who is attached to one end of an 85-m long bungee cord that has its other end tied to a bridge, jumps off the bridge and toward the river below. When stretched, the bungee cord acts like a spring and provides a force on the jumper that increases linearly as the cord is stretched. When the bungee cord is stretched to its maximum length, it exerts a 2.2 kN force on the jumper. If the bungee cord is stretched beyond its equilibrium length for a duration of 1.2 seconds, what is the impulse delivered to the bungee jumper
Answer:
The impulse delivered to the bungee jumper is 1.32 kN.s
Explanation:
The situation can be shown graphically as shown in the figure.
Impulse delivered to the bungee jumper = Area under the curve.
The curve represents a triangle and the area of traiangle = (1/2)base×height
The base of the triangle from the graph = 1.2 seconds.
The height of the triangle from the graph = 2.2 kN
Thus,
Impulse = (1/2)×(1.2 seconds)×(2.2 kN) = 1.32 kN.s
A motorboat travels 92 km in 2 hours going upstream. It travels 132 km going downstream in the same amount of time. What is the rate of the boat in still water and what is the rate of the current?
Answer:
The speed on boat in still water is [tex]56 \frac{km}{h}[/tex] and the rate of the current is [tex]10 \frac{km}{h}[/tex]
Explanation:
Since speed , [tex]v= \frac{Distance\, traveled(D)}{Time\, taken(t)}[/tex]
Therefore speed of motor boat while traveling upstream is
[tex]v_{upstream}=\frac{92}{2}\frac{km}{h}=46\frac{km}{h}[/tex]
and speed of motor boat while traveling downstream is
[tex]v_{downstream}=\frac{132}{2}\frac{km}{h}=66\frac{km}{h}[/tex]
Let speed of boat in still water be [tex]v_b[/tex] and rate of current be [tex]v_w[/tex]
Therefore [tex]v_{upstream}=v_b-v_w=46\frac{km}{h}[/tex] ----(A)
and [tex]v_{downstream}=v_b+v_w=66\frac{km}{h}[/tex] ------(B)
Adding equation (A) and (B) we get
[tex]2v_b= (46+66) \frac{km}{h}=112 \frac{km}{h}[/tex]
=>[tex]v_b= 56 \frac{km}{h}[/tex] ------(C)
Substituting the value of [tex]v_b[/tex] in equation (A) we get
[tex]v_w= 10 \frac{km}{h}[/tex]
Thus the speed on boat in still water is [tex]56 \frac{km}{h}[/tex] and the rate of the current is [tex]10 \frac{km}{h}[/tex]
A mass of gas at pressure P and temperature T (degrees Kelvin) and volume V satisfies the equation T = KPV where K is a constant. The initial temperature is 300 degrees Kelvin, the inital volume is 4 cubic centimeters, and the inital pressure is 4 [The units are N per square centimeter. This is force per unit area, which is what pressure is.] If the pressure increases by 7 % and the volume increases by 0.07 cubic centimeters, approximately how much does the temperature change by? [hint: use the initial information to find K]
The equation is T = KPV
Using the initial information you have, solve for K:
300 = K(4)(4)
Simplify:
300 = K(16)
Divide both sides by 16
K = 300/16
K = 18.75
Now if pressure increases by 7%, the new pressure would be 4 x 1.07 = 4.28
Volume increases by 0.07, so the new volume would be 4 + 0.07 = 4.07
Now solve for t:
T = 18.75(4.28)(4.07)
T = 326.6175
Now subtract the new temperature from the original one:
326.6175 - 300 = 26.6175 increase ( Round answer as needed).
A basketball player grabbing a rebound jumps 76.0 cm vertically. How much total time (ascent and descent) does the player spend (a) in the top 15.0 cm of this jump and (b) in the bottom 15.0 cm? Do your results explain why such players seem to hang in the air at the top of a jump?
a) we can answer the first part of this by recognizing the player rises 0.76m, reaches the apex of motion, and then falls back to the ground we can ask how
long it takes to fall 0.13 m from rest: dist = 1/2 gt^2 or t=sqrt[2d/g] t=0.175
s this is the time to fall from the top; it would take the same time to travel
upward the final 0.13 m, so the total time spent in the upper 0.15 m is 2x0.175
= 0.35s
b) there are a couple of ways of finding thetime it takes to travel the bottom 0.13m first way: we can use d=1/2gt^2 twice
to solve this problem the time it takes to fall the final 0.13 m is: time it
takes to fall 0.76 m - time it takes to fall 0.63 m t = sqrt[2d/g] = 0.399 s to
fall 0.76 m, and this equation yields it takes 0.359 s to fall 0.63 m, so it
takes 0.04 s to fall the final 0.13 m. The total time spent in the lower 0.13 m
is then twice this, or 0.08s
Answer:
Part a)
[tex]T = 0.35 s[/tex]
Part b)
[tex]T' = 0.041 s[/tex]
So for top 15 cm the time interval is sufficiently larger than the time interval of last 15 cm
Explanation:
Part a)
Maximum height reached is
H = 76 cm
now the velocity of the player at starting position is given as
[tex]v_f^2 - v_i^2 = 2ad[/tex]
[tex]0 - v^2 = 2(-9.81)(0.76)[/tex]
[tex]v = 3.86 m/s[/tex]
time taken by it in top 15 cm position is given as
[tex]y = \frac{1}{2}gt^2[/tex]
[tex]0.15 = \frac{1}{2}(9.81)t^2[/tex]
[tex]t = 0.175 s[/tex]
so total time in that position is double because in that position first it will go up and then go down
[tex]T = 0.35 s[/tex]
Part b)
Now for bottom position of 15 cm first we will find the time to reach (76 - 15)cm have
[tex]H = \frac{1}{2}gt^2[/tex]
[tex](0.76 - 0.15) = \frac{1}{2}(9.81)t^2[/tex]
[tex]t_1 = 0.352 s[/tex]
now for total time to drop
[tex]t_2 = \sqrt{\frac{2H}{g}}[/tex]
[tex]t_2 = 0.394 s[/tex]
so time interval of last 15 cm is given as
[tex]t' = 0.394 - 0.352[/tex]
[tex]T' = 0.041 s[/tex]
So for top 15 cm the time interval is sufficiently larger than the time interval of last 15 cm
In Ptolemy's Earth-centered model for the solar system, Venus's phase is never full as viewed from Earth because it always lies between Earth and the Sun. In reality, as Galileo first recognized, Venus is __________.
Explanation:
Galileo observed that Venus presented phases (such as those of the moon) together with a variation in size; observations that are only compatible with the fact that Venus rotates around the Sun and not around Earth.
This is because Venus presented its smaller size when it was in full phase and the largest size when it was in the new one, when it is between the Sun and the Earth.
In other words: When Venus is in its full phase it is not possible to observe it from the Earth because always in this phase, Venus, the Sun and the Earth are in conjunction (or aligned). This means the Sun is between Venus and Earth, in the orbit that both planets describe around this star.
Therefore, from the Earth, the Sun covers Venus.
This fact along with other discoveries were presented by Galileo to the Catholic Church (which supported the geocentric theory at that time) as a proof that completely refuted Ptolemy's geocentric system and affirmed Copernicus' heliocentric theory.
Can someone please help me with this physics problem? I'd really appreciate any help I can get!
Answer:
560 m
Explanation:
"A projectile is fired at time t = 0.0 s from point 0 at the edge of a cliff, with initial velocity components of v₀ₓ = 30 m/s and v₀ᵧ = 100 m/s. The projectile rises, and then falls into the sea at point P. The time of flight of the projectile is 25 s. Assume air resistance is negligible. What is the height of the cliff?"
Use constant acceleration equation in the y direction.
y = y₀ + v₀ t + ½ gt²
0 = h + (100 m/s) (25 s) + ½ (-9.8 m/s²) (25 s)²
h = 560 m
The height of the cliff is 560 m.
wo tiny spheres have the same mass and carry charges of the same magnitude. The mass of each sphere is 2.0 × 10−6 kg. The gravitational force that each sphere exerts on the other is balanced by the electric force. determine the charge magnitude.
Answer:
Charge, [tex]q=1.72\times 10^{-16}\ C[/tex]
Explanation:
It is given that, two tiny spheres have the same mass and carry charges of the same magnitude. Let charge on both sphere is q.
Also, the gravitational force that each sphere exerts on the other is balanced by the electric force i.e.
[tex]F_g=F_e[/tex]
[tex]G\dfrac{m^2}{r^2}=k\dfrac{q^2}{r^2}[/tex]
[tex]q=\sqrt{\dfrac{Gm^2}{k}}[/tex]
Where
G is the universal gravitational constant
k is the electrostatic constant
[tex]q=\sqrt{\dfrac{6.67\times 10^{-11}\ Nm^2/kg^2\times (2\times 10^{-6}\ kg)^2}{9\times 10^9\ Nm^2/C^2}}[/tex]
[tex]q=1.72\times 10^{-16}\ C[/tex]
So, the charge on both the spheres is [tex]1.72\times 10^{-16}\ C[/tex]. Hence, this is the required solution.
Answer:
[tex] q =5.439\times 10^{-17}C[/tex]
Explanation:
Given:
Mass of the tiny sphere, M = 2.0 × 10⁻⁶ kg
also masses are equal i.e M₁ = M₂
Now,
the gravitational force between the two masses M₁ and M₂ is given as:
[tex]F_G = \frac{GM_1M_2}{r^2}[/tex]
where,
G is the gravitational force constant = 6.67 x 10⁻¹¹ m³/kg.s²
r = center to center distance between the masses
also,
Electric force between the charges is given as
[tex]F_e=\frac{kq_1q_2}{r^2}[/tex]
where,
q₁ and q₂ are the charges and also it is given that q₁=q₂=q
k is the coulomb's law constant = 9.0 x 10⁹ N.m²/C²
since it is mentioned that [tex]F_G = F_e[/tex]
we have
[tex]\frac{kq_1q_2}{r^2} = \frac{GM_1M_2}{r^2}[/tex]
or
[tex]{9\times 10^9\times q^2} ={6.67\times 10^{-11}(2.0\times 10^{-6})^2}[/tex]
or
[tex] q =5.439\times 10^{-17}C[/tex]
The Kinetic energy, K, of an object with mass m moving with velocity v can be found using the formula - E_{\text{k}}={\tfrac {1}{2}}mv^{2}
. A scientist measured the velocity of a 5-kilogram object and a 20-kilogram object in an experiment. If the velocity of the 5-kilogram object was twice the velocity of the 20-kilogram object, what was the ratio of the kinetic energy of the 5 kilogram object to the kinetic energy of the 20-kilogram object?
Answer:
The ratio of kinetic energies of 5 kg object to 20 kg object is 1:1.
Explanation:
Kinetic energy is defined as energy possessed by an object due to its motion.It is calculated by:
[tex]K.E=\frac{1}{2}mv^2[/tex]
Kinetic energy of the 5 kg object.
Mass of object,m = 5 kg
Velocity of an object = v
[tex]K.E=\frac{1}{2}mv^2=\frac{1}{2}\times 5kg\times v^2[/tex]
Kinetic energy of the 20 kg object.
Mass of object,m' = 20 kg
Velocity of an object = v'
[tex]K.E=\frac{1}{2}mv^2=\frac{1}{2}\times 20kg\times v'^2[/tex]
The ratio of the kinetic energy of the 5 kilogram object to the kinetic energy of the 20-kilogram object:
[tex]\frac{K.E}{K.E'}=\frac{\frac{1}{2}\times 5kg\times v^2}{\frac{1}{2}\times 20kg\times v'^2}[/tex]
Given that, v = 2v'
[tex]\frac{K.E}{K.E'}=\frac{1}{1}[/tex]
The ratio of kinetic energies of 5 kg object to 20 kg object is 1:1.
A tennis ball of mass 44.0 g is held just above a basketball of mass 594 g. With their centers vertically aligned, both are released from rest at the same moment, to fall through a distance of 1.08 m, (a) Find the magnitude of the downward velocity with which the basketball reaches the ground. Assume that an elastic collision with the ground instantaneously reverses the velocity of the basketball while the tennis ball is still moving down. (b) Next, the two balls meet in an elastic collision. To what height does the tennis ball rebound?
Answer:
u = 4.6 m/s
h = 8.01 m
Explanation:
Given:
Mass of the tennis ball, m = 44.0 g
Mass of the basket ball, M = 594 g
Height of fall, h = 1.08m
Now,
we have
[tex]u^2-u'^2 = 2as[/tex]
where, s = distance = h
a = acceleration
u = final speed before the collision
u' = initial speed
since it is free fall case
thus,
a = g = acceleration due to gravity
u' = 0
thus we have
[tex]u^2-0^2 = 2\times9.8\tiimes1.08[/tex]
or
[tex]u = \sqrt{21.168}[/tex]
or
u = 4.6 m/s
b) Now after the bounce, the ball moves with the same velocity
thus, v = v₂
thus,
final speed ([tex]v_f[/tex]) = v = 4.6 m/s
Then conservation of energy says
[tex]\frac{1}{2}mu_1^2+\frac{1}{2}Mu_2^2 = \frac{1}{2}mv_1^2+\frac{1}{2}Mv_2^2[/tex]
also
applying the concept of conservation of momentum
we have
mu₁ + Mu₂ = mv₁ + Mv₂
u₁ =velocity of the tennis ball before collision = -4.6 m/s
u₂ = velocity of the basketball before collision= 4.6 m/s
v₁ = velocity of the tennis ball after collision
v₂ = velocity of the basketball after collision
substituting the values in the equation, we get
Now,
solving both the equations simultaneously we get
[tex]v = (\frac{2M}{m+M})u_1+(\frac{m-M}{m+M})u_2[/tex]
substituting the values in the above equation we get
[tex]v = (\frac{2\times594}{44+594})(-4.6)+(\frac{44-594}{44+594})4.6[/tex]
or
[tex]v = -8.565-3.965[/tex]
or
[tex]v = -12.53m/s[/tex]
here negative sign depicts the motion of the ball in the upward direction
now the kinetic energy of the tennis ball
[tex]K.E = \frac{1}{2}mv^2[/tex]
or
[tex]K.E = \frac{1}{2}44\times 10^{-3}kg\times 12.53^2[/tex]
or
K.E = 3.45 J
also at the height the K.E will be the potential energy of the tennis ball
thus,
3.45 J = mgh
or
3.45 = 44 × 10⁻³ × 9.8 × h
h = 8.01 m
The magnitude of the downward velocity with which the basketball reaches the ground is 4.51 m/s. The height to which the tennis ball rebounds after an elastic collision with the basketball can be found by solving for the velocity of the tennis ball after the collision and using the equation h = (v2')² / (2g).
Explanation:To find the magnitude of the downward velocity with which the basketball reaches the ground, we can use the equation v = gt, where g is the acceleration due to gravity. Since both the basketball and tennis ball are released from rest and fall through the same distance, they will reach the ground at the same time. Therefore, the time it takes for the basketball to reach the ground is the same as the time it takes for the tennis ball to fall and bounce back up:
t = sqrt(2h/g)
where h is the distance the balls fall. We can substitute the given values into the equation to find the time:
t = sqrt(2 * 1.08m / 9.8m/s²) = 0.46 s
Therefore, the magnitude of the downward velocity with which the basketball reaches the ground is given by v = gt:
v = 9.8m/s² * 0.46s = 4.51 m/s
For part (b), to find the height to which the tennis ball rebounds after an elastic collision with the basketball, we can use the conservation of momentum and the conservation of kinetic energy. Since the collision is elastic, the total momentum and the total kinetic energy of the two balls before the collision are equal to the total momentum and total kinetic energy after the collision:
m1v1 + m2v2 = m1v1' + m2v2'
1/2m1v1² + 1/2m2v2² = 1/2m1v1'² + 1/2m2v2'²
We can substitute the given values into the equations and solve for v2', the velocity of the tennis ball after the collision:
0.044kg * 0m/s + 0.594kg * 4.51m/s = 0.044kg * v1' + 0.594kg * v2'
1/2 * 0.044kg * 0m/s² + 1/2 * 0.594kg * (4.51m/s)² = 1/2 * 0.044kg * v1'² + 1/2 * 0.594kg * v2'²
From these equations, we can solve for v2', the velocity of the tennis ball after the collision. The height to which the tennis ball rebounds can be found using the equation:
h = (v2')² / (2g)
We can substitute the calculated value of v2' into the equation to find the height:
h = (v2')² / (2 * 9.8m/s²)
Learn more about Projectile Motion here:https://brainly.com/question/29545516
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A sample of an ideal gas has a volume of 2.37 L at 2.80×102 K and 1.15 atm. Calculate the pressure when the volume is 1.68 L and the temperature is 304 K.
Answer:
[tex]p_2 = 1.76 atm[/tex]
Explanation:
given data:
v_1 = 2.37 L
v_2 = 1.68 L
p_1 =1.15 atm
p_2 = ?
t_1 = 280 K
t_2 = 304 K
from Gas Law Equation
, WE HAVE
[tex]\frac{p_1 v_1}{t_1} =\frac{p_2 v_2}{t_2}[/tex]
Putting the values
[tex]\frac{1.15*2.37}{280} =\frac{p_2 *1.68}{304}[/tex]
[tex]9.733*10^{-3} = \frac{p_2 *1.68}{304}[/tex]
[tex]9.733*10^{-3}*304 = p_2*1.68[/tex]
[tex]\frac{9.733*10^{-3}*304}{1.68} =p_2[/tex]
[tex]p_2= 1.76 atm[/tex]
Which of the fundamental forces explains the structure of atoms and molecules? gravitational force
electromagnetic force
weak nuclear force
strong nuclear force
pls help me
Answer:
Strong nuclear force
Explanation:
Strong nuclear force (which is the strongest of the forces of the universe) is responsible for the attractive force between quarks to form nucleons (protons and neutrons). It is the reason why the protons (that are positive in charge) do not fly apart due to electromagnetic repulsion in the nucleus of an atom.
A diffraction grating with 750 slits per mm is illuminated by light which gives a first-order diffraction angle of 34.0°. What is the wavelength of the light?
Explanation:
The diffraction angles [tex]\theta_{n}[/tex] when we have a slit divided into [tex]n[/tex] parts are obtained by the following equation:
[tex]dsin\theta_{n}=n\lambda[/tex] (1)
Where:
[tex]d[/tex] is the width of the slit
[tex]\lambda[/tex] is the wavelength of the light
[tex]n[/tex] is an integer different from zero
Now, the first-order diffraction angle is given when [tex]n=1[/tex], hence equation (1) becomes:
[tex]dsin\theta_{1}=\lambda[/tex] (2)
We know:
[tex]\theta_{1}=34\°[/tex]
In addition we are told the diffraction grating has 750 slits per mm, this means:
[tex]d=\frac{1mm}{750}[/tex]
Solving (2) with the known values we will find [tex]\lambda[/tex]:
[tex]\lambda=(\frac{1mm}{750})sin(34\°)[/tex] (3)
[tex]\lambda=0.00074559mm[/tex] (4)
Knowing [tex]1mm=10^{6}nm[/tex]:
[tex]\lambda=745.59nm[/tex] >>>This is the wavelength of the light, wich corresponds to red.
A rock thrown with speed 7.50 m/s and launch angle 30.0 ∘ (above the horizontal) travels a horizontal distance of d = 18.0 m before hitting the ground. From what height was the rock thrown? Use the value g = 9.800 m/s2 for the free-fall acceleration.
Answer:
height from where rock was thrown is 27.916 m
Explanation:
speed = 7.50 m/s
θ = 30°
g= 9.8 m/s²
horizontal distance = 18 m
time require for vertical displacement
[tex]time = \frac{distance}{velocity} \\t = \frac{18}{7.5\ cos30^0}[/tex]
t = 2.8 sec
now for calculation of height
s = ut + 0.5 a t²
-h = v sinθ× t + 0.5 ×(-9.8)× (2.8²)
-h = 7.5 sin30°× 2.8 - 0.5 ×(9.8)× (2.8²)
-h = -27.916 m
h= 27.916 m
height from where rock was thrown is 27.916 m
Final answer:
To find the height from which the rock was thrown, we can use the equations of projectile motion to calculate the time it takes for the rock to hit the ground and then find the height using another equation. The rock was thrown from a height of 5.7 meters.
Explanation:
To find the height from which the rock was thrown, first, we need to determine the time it takes for the rock to hit the ground.
Using the equation d = v_iy * t + (1/2) * g * t^2, where d is the vertical distance, v_iy is the initial vertical velocity, t is the time, and g is the acceleration due to gravity, plug in the values:
d = 0 (since the rock starts and ends at the same height)
v_iy = 7.5 m/s * sin(30°)
g = 9.8 m/s^2
Solving for t, we get t = 1.22 s.
Next, we can find the height by using the equation d = v_iy * t - (1/2) * g * t^2 and plugging in the values:
d = ?, the height we want to find
v_iy = 7.5 m/s * sin(30°)
t = 1.22 s
g = 9.8 m/s^2
Solving for d, we get d = 5.7 m.
Therefore, the rock was thrown from a height of 5.7 meters.
Urban cities like Atlanta have to contend with a serious problem like pollution. Drivers in California are testing out a car that is fueled by hyrodgen; therefore, the emissions produced are water vapor. Read the article from the link below and answer the following questions:
goo.gl/h93L43
1. What does the author mean by the statement:
“If we’re really going to make a significant reduction in carbon emissions, you can only do that with fuel-cell vehicles in the mix"?
2. What are some of the challenges with these type of vehicles? How can these challenges be overcome?
3. Do you think fuel celled cars are a viable answer to decrease pollution why or why not?
1. With this statement, the author is referring to the fact that the vehicles are one of the largest polluters of the air. In order to reduce the pollution, the vehicles that are used will need to be changed, and with it the pollution will decrease significantly. The reduction of the pollution will come because the vehicles on hydrogen will not cause any pollution, so the enormous amounts of carbon dioxide released from the combustion of the engines will be thing of the past.
2. There are several challenges with this type of vehicles in order for them to replace the fossil fuel driven ones. The big price is one of the factors, as the majority of the people can not afford these cars. Another problem is that these vehicles are not as fast as the fossil fuel driven ones, and lot of people enjoy fast driving, despite it not being safe. There are millions of vehicles out there on the roads, and changing all of them with hydrogen vehicles will take a lot of time, as lot of those vehicles are new ones, so the people will not be willing to just throw them away and leave them rot in their garages. In order for the change of the driving park to be accomplished, the prices should go down, the people to be more serious about the environment and its protection, and patience as several decades will probably be needed for a change like this to be competed.
3. The fuel celled cars are a viable answer to decrease the pollution, as they are not causing any pollution, but instead will stop the process of large emissions of carbon dioxide from the fossil fueled cars. While this method is a good one, it should not be the only, as on its own it can not have the desirable effect, but instead all the major polluters should be included in the process. The industry and the production of energy are one of the major polluters as well, so they will need to follow the example, as if they not, the problem will stay, considering that the industry is constantly growing and the demand for energy is constantly growing too.
A diver exhales a bubble with a volume of 250 mL at a pressure of 2.4 atm and a temperature of 15°C. What is the volume of the bubble when it reaches the surface where the pressure is 1.0 atm and the temperature is 27°C?
Answer: 624.98 mL
Explanation:
According to the Ideal Gas Law:
[tex]\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{2}}{T_{2}}[/tex] (1)
Where:
[tex]P_{1}=2.4 atm[/tex] is the pressure of the bubble under the surface
[tex]V_{1}=250 mL[/tex] is the volume of the bubble under the surface
[tex]T_{1}=15\°C + 273.15=288.15 K[/tex] is the temperature of the bubble under the surface
[tex]P_{2}=1 atm[/tex] is the pressure of the bubble at the surface
[tex]V_{2}[/tex] is the volume of the bubble at the surface
[tex]T_{2}=27\°C + 273.15=300.15 K[/tex] is the temperature of the bubble at the surface
So, we have to find [tex]V_{2}[/tex]:
[tex]V_{2}=\frac{P_{1}V_{1}T_{2}}{T_{1}P_{2}}[/tex] (2)
[tex]V_{2}=\frac{(2.4 atm)(250 mL)(300.15 K)}{(288.15 K)(1 atm)}[/tex] (3)
Finally:
[tex]V_{2}=624.98 mL[/tex] This is the volume of the bubble when it reaches the surface
The volume of the bubble when it reaches the surface is about 625 mL
Further explanationThe basic formula of pressure that needs to be recalled is:
Pressure = Force / Cross-sectional Area
or symbolized:
[tex]\large {\boxed {P = F \div A} }[/tex]
P = Pressure (Pa)
F = Force (N)
A = Cross-sectional Area (m²)
Let us now tackle the problem !
In this problem , we will use Ideal Gas Law as follows:
Given:
Initial Volume = V₁ = 250 mL
Initial Pressure = P₁ = 2.4 atm
Initial Temperature = T₁ = 15 + 273 = 288 K
Final Pressure = P₂ = 1.0 atm
Final Temperature = T₂ = 27 + 273 = 300 K
Unknown:
Final Volume = V₂ = ?
Solution:
[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]
[tex]\frac{2.4(250)}{288} = \frac{1.0V_2}{300}[/tex]
[tex]\frac{600}{288} = \frac{1.0V_2}{300}[/tex]
[tex]\frac{25}{12} = \frac{V_2}{300}[/tex]
[tex]V_2 = \frac{25}{12} \times 300[/tex]
[tex]V_2 = 625 \texttt{ mL}[/tex]
[tex]\texttt{ }[/tex]
Learn moreMinimum Coefficient of Static Friction : https://brainly.com/question/5884009The Pressure In A Sealed Plastic Container : https://brainly.com/question/10209135Effect of Earth’s Gravity on Objects : https://brainly.com/question/8844454Answer detailsGrade: High School
Subject: Physics
Chapter: Pressure
Keywords: Gravity , Unit , Magnitude , Attraction , Distance , Mass , Newton , Law , Gravitational , Constant , Liquid , Pressure
A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed of 1.7 m/s, how fast is the length of his shadow on the building decreasing when he is 4 m from the building?
Answer:
0.6375 m/s
Explanation:
Let x be the distance of the man from the building
from the figure attached
initially the value of x=12
Given:
[tex]\frac{dx}{dt}=-1.7m/s[/tex]
where the negative sign depicts that the distance of the man from the building is decreasing.
Now, Let The length of the shadow be = y
we have to calculate [tex]\frac{dy}{dt}[/tex] when x=4
from the similar triangles
we have,
[tex]\frac{2}{12-x}=\frac{y}{12}[/tex]
or
[tex]y=\frac{24}{12-x}[/tex]
Differentiating with respect to time 't' we get
[tex]\frac{dy}{dt}=-\frac{24}{12-x}^2\frac{-dx}{dt}[/tex]
or
[tex]\frac{dy}{dt}=\frac{24}{12-x}^2\frac{dx}{dt}[/tex]
Now for x = 4, and [tex]\frac{dx}{dt}=-1.7m/s[/tex] we have,
[tex]\frac{dy}{dt}=\frac{24}{12-4}^2\times (-1.7)[/tex]
or
[tex]\frac{dy}{dt}=-0.6375m/s[/tex]
here, the negative sign depicts the decrease in length and in the question it is asked the decreasing rate thus, the answer is 0.6375m/s
A small cylinder made of a diamagnetic material is brought near a bar magnet. One end of the cylinder is brought near the North pole of the magnet and is repelled. What happens when the other end of the cylinder is brought near the North pole of the magnet? (A) The other end of the cylinder will be repelled by the magnet.(B) The other end of the cylinder will not be affected by the magnet.(C) The other end of the cylinder will be attracted more strongly by the magnet.(D) The other end of the cylinder will be attracted less strongly by the magnet.(E) The other end of the cylinder will be attracted by the magnet.
Answer: Option (A) is the correct answer.
Explanation:
A diamagnetic material does not contain any unpaired electrons and therefore, in a magnetic field direction they will always flow in the direction opposite to the magnetic field.
Hence, a diamagnetic material will always repel the magnetic field whenever it comes in contact with that.
Thus, we can conclude that when the other end of the cylinder is brought near the North pole of the magnet then the other end of the cylinder will be repelled by the magnet.