Let's begin with the angular acceleration of a compact disk (CD). To play music the CD must rotate at high speed while a laser reads data encoded in a spiral pattern on the disk. The disc has radius R=6.0cm=0.060m; when data are being read, it spins at 7200 rev/min. What is the CD's angular velocity ω in radians per second? How much time is required for it to rotate through 90∘? If it starts from rest and reaches full speed in 4.0 s, what is its average angular acceleration?

Answers

Answer 1
Final answer:

The angular velocity of the CD is 754.4 rad/s. The time it takes for the CD to rotate through 90 degrees is 0.0021 seconds. The average angular acceleration of the CD is 188.6 rad/s².

Explanation:

To calculate the angular velocity of the CD, we can convert the given 7200 rev/min to radians per second. Since one revolution is equal to 2π radians, we can use the conversion factor to find the angular velocity. Thus, the angular velocity of the CD is 754.4 rad/s.

To calculate the time it takes for the CD to rotate through 90 degrees, we need to find the fraction of the total rotation that corresponds to 90 degrees. Since a full rotation is 360 degrees or 2π radians, 90 degrees is equal to π/2 radians. We can then use the formula Δθ = ωΔt to find the time it takes, where Δθ is the angle in radians, ω is the angular velocity, and Δt is the time. Rearranging the formula, we have Δt = Δθ/ω. Substituting the values, we get Δt = π/2 / 754.4 = 0.0021 seconds.

The average angular acceleration can be found using the formula α = (ωf - ωi) / Δt, where α is the angular acceleration, ωf is the final angular velocity, ωi is the initial angular velocity, and Δt is the time interval. The CD starts from rest and reaches full speed in 4 seconds, so the initial angular velocity is 0. Using the given full speed of 7200 rev/min, we can convert it to radians per second and use it as the final angular velocity. Thus, the average angular acceleration is α = (754.4 rad/s - 0 rad/s) / 4 s = 188.6 rad/s².

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Related Questions

A projectile of mass 0.850 kg is shot straight up with an initial speed of 30.0 m/s. (a) How high would it go if there were no air resistance? (b) If the projectile rises to a maximum height of only 36.7 m, determine the magnitude of the average force due to air resistance.

Answers

Answer:

a) 45.87 m

b) 2.08 N

Explanation:

Mass of projectile=0.85 kg=m

Velocity of projectile=30 m/s=u = initial velocity

Final velocity =0

g= acceleration due to gravity=9.81 m/s²

h=maximum height of the projectile

a) In this case loss of Kinetic energy (K.E.) = loss in potential energy (P.E.)

ΔK.E.=ΔP.E.

[tex]\frac{1}{2}mu^2-\frac{1}{2}mv^2=mgh[/tex]

[tex]\frac{1}{2}m\times u^2=mgh\\\Rightarrow h=\frac {u^2}{2\times g}\\\Rightarrow h=\frac {30^2}{2\times 9.81}\\\therefore h=45.87\ m[/tex]

b) h'=height of the projectile=36.7 m

F=Average force due to air resistance

There will be a loss of P.E. due to air resistance

ΔP.E.=mg(h-h')

F×h'=mg(h-h')

F×36.7=0.85×9.81(45.87-36.7)

[tex]F=\frac{0.85\times 9.81(45.87-36.7)}{36.7}[/tex]

∴ F=2.08 Newton

The transmission of heat requiring the movement of a liquid or a gas is A. conduction B. radiation. C. convection. D. transduction.

Answers

Answer:

convection C

Explanation:

Answer:

C. convection

Which of the following systems has constant kinetic and potential energies? A car moving along a level road at constant speed
A car moving up a hill at constant speed
A car moving down a hill at constant speed
All of the above

Answers

A car moving along a level road at constant speed

A long solenoid has a length of 0.67 m and contains 1700 turns of wire. There is a current of 5.5 A in the wire. What is the magnitude of the magnetic field within the solenoid?

Answers

B = 17.5mT.

A solenoid is a coil formed by a wire (usually copper) wound into a cylindrical spiral shape capable of creating a magnetic field that is extremely uniform and intense inside, and very weak outside.

To calculate the magnetic field generated inside the solenoid through which a current flows is given by the equation:

B = μ₀nI

Where  μ₀ is the constant of magnetic proportionality of the vacuum (4π x 10⁻⁷T.m/A), n is the relation between the number of turns of wire and its length given by N/L and I is the current flowing through the solenoid.

Given a long solenoid of length 0.67m, 1700.00 turns of wire and a current flowing through the wire of 5.50A. Calculate the magnetic field inside the solenoid.

B = (4π x 10⁻⁷T.m/A)(1700turns/0.67m)(5.50A)

B = 0.0175T

B = 17.5mT

A potential difference of 35 mV is developed across the ends of a 12.0-cm-long wire as it moves through a 0.27 T uniform magnetic field at a speed of 4.0 m/s. The magnetic field is perpendicular to the axis of the wire. Part A What is the angle between the magnetic field and the wire's velocity?

Answers

Answer:

Angle between the magnetic field and the wire's velocity is 15.66 degrees.

Explanation:

It is given that,

Potential difference or emf, V = 35 mV = 0.035 V

Length of wire, l = 12 cm= 0.12 m

Magnetic field, B = 0.27 T

Speed, v = 4 m/s

We need to find the angle between the magnetic field and the wire's velocity. We know that emf is given by :

[tex]\epsilon=Blv\ sin\theta[/tex]

[tex]sin\theta=\dfrac{\epsilon}{Blv}[/tex]

[tex]sin\theta=\dfrac{0.035\ V}{0.27\ T\times 0.12\ m\times 4\ m/s}[/tex]

[tex]sin\theta=0.25[/tex]

[tex]\theta=15.66^{\circ}[/tex]

So, the angle between the magnetic field and the wire's velocity is 15.66 degrees.

Final answer:

The angle between the wire's velocity and the magnetic field, when they are perpendicular to each other, is 90 degrees. This impacts the force exerted on the wire in the magnetic field.

Explanation:

The question pertains to the interaction of a moving conductor wire in a magnetic field - a fundamental concept in electromagnetism. From the question, the velocity of the wire is perpendicular to the magnetic field. This is the key because the magnetic force on a moving charge within a magnetic field depends on the angle between the charge's velocity and the direction of the magnetic field.

According to the fundamentals of physics, when velocity is perpendicular to the magnetic field, the angle between them is 90 degrees. The force exerted on the wire due to the magnetic field is then given by F = qvBsinθ, where q is the charge, v is the velocity, B is the magnetic field, and θ is the angle between the velocity and the magnetic field. With θ being 90 degrees, the sin(90°) equals 1, and this simplifies the calculation. So the angle developed between the magnetic field and the wire's velocity is 90 degrees in this case.

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What is the minimum work needed to push a 925-kg car 207 m up along a 14.5° incline? Ignore friction.

Answers

Answer:

4.7 x 10⁵ J

Explanation:

m = mass of the car = 925 kg

d = distance traveled parallel to incline = 207 m

θ = angle of the slope = 14.5 deg

Force applied to move the car up is given as

F = mg Sinθ                                               eq-1

minimum work needed is given as

W = F d

using eq-1

W =  mgd Sinθ

inserting the values

W = (925)(9.8)(207) Sin14.5

W = 4.7 x 10⁵ J

When the molecules in a body move with increased speed, it's possible that the body will change from a: A) gas to a solid B) gas to a liquid C) liquid to a solid. D) liquid to a gas.

Answers

Answer:

Liquid to a gas

Explanation:

When the molecules in a body move with increased speed, it's possible that the body will change from liquid to gas. The speed is increasing means they have more kinetic energy. The molecules of gas are very far apart from each other. They have much space between them so that they can move freely.

So, when the molecules move with increased speed, the body will change from liquid to gas. Hence, the correct option is (d) " liquid to gas".

A motorcycle is moving at 18 m/s when its brakes are applied, bringing the cycle to rest in 4.7 s. To the nearest meter, how far does the motorcycle travel while coming to a stop?

Answers

Answer:

the motorcycle travels 42.4 meters until it stops.

Explanation:

Vi= 18 m/s

Vf= 0 m/s

t= 4.7 sec

Vf= Vi - a*t

deceleration:

a= Vi/t

a= 18m/s  / 4.7 sec =>  a=-3.82 m/s²

x= Vi*t - (a * t²)/2

x= 42.4m

A block of mass 0.221 kg is placed on top of a light, vertical spring of force constant 5365 N/m and pushed downward so that the spring is compressed by 0.097 m. After the block is released from rest, it travels upward and then leaves the spring. To what maximum height above the point of release does it rise?

Answers

Answer:

The maximum height above the point of release is 11.653 m.

Explanation:

Given that,

Mass of block = 0.221 kg

Spring constant k = 5365 N/m

Distance x = 0.097 m

We need to calculate the height

Using stored energy in spring

[tex]U=\dfrac{1}{2}kx^2[/tex]...(I)

Using gravitational potential energy

[tex]U' =mgh[/tex]....(II)

Using energy of conservation

[tex]E_{i}=E_{f}[/tex]

[tex]U_{i}+U'_{i}=U_{f}+U'_{f}[/tex]

[tex]\dfrac{1}{2}kx^2+0=0+mgh[/tex]

[tex]h=\dfrac{kx^2}{2mg}[/tex]

Where, k = spring constant

m = mass of the block

x = distance

g = acceleration due to gravity

Put the value in the equation

[tex]h=\dfrac{5365\times(0.097)^2}{2\times0.221\times9.8}[/tex]

[tex]h=11.653\ m[/tex]

Hence, The maximum height above the point of release is 11.653 m.

A sports car accelerates in third gear from 48.5 km/h to 80.2 km/h in 3.6 s. (a) What is the average acceleration of the car? (in m/s^2)
(b) If the car maintained this acceleration after reaching 80.2 km/h, how fast would it be moving 4.0 seconds later? (in km/h)

Answers

Final answer:

The average acceleration of the car is 2.45 m/s^2. If the car maintains this acceleration, it would be moving at a speed of 117.65 km/h 4.0 seconds later.

Explanation:

(a) To find the average acceleration, we can use the formula: average acceleration (a) = (final velocity - initial velocity) / time. Converting the velocities to m/s gives us 13.47 m/s and 22.28 m/s, respectively. Plugging in the values, we get: a = (22.28 - 13.47) m/s / 3.6 s = 2.45 m/s^2. Therefore, the average acceleration of the car is 2.45 m/s^2.

(b) Since the car is maintaining the same acceleration, we can use the kinematic equation: final velocity = initial velocity + acceleration * time. Converting the initial velocity to m/s, we have 22.28 m/s. Plugging in the values, we get: final velocity = 22.28 m/s + 2.45 m/s^2 * 4.0 s = 32.68 m/s. Converting back to km/h gives us 32.68 m/s * 3.6 km/h/m = 117.65 km/h.

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Final answer:

The average acceleration of the sports car is approximately 2.446 m/s^2, and if it maintained this acceleration for an additional 4.0 seconds, it would be moving at roughly 115.4 km/h.

Explanation:

Calculating the Average Acceleration and Future Velocity

To find the average acceleration (a) of the car, we use the formula a = (v_f - v_i) / t, where v_f is the final velocity, v_i is the initial velocity, and t is the time taken for the change in velocity. First, we need to convert the velocities from km/h to m/s by multiplying by (1000 m/km) / (3600 s/h).

v_i = 48.5 km/h = (48.5 * 1000) / 3600 m/s ≈ 13.472 m/s

v_f = 80.2 km/h = (80.2 * 1000) / 3600 m/s ≈ 22.278 m/s

Now, we can calculate the average acceleration:

a = (22.278 m/s - 13.472 m/s) / 3.6 s ≈ 2.446 m/s²

To find the velocity 4.0 seconds after the car reaches 80.2 km/h, we use the formula v = v_f + a * t:

v = 22.278 m/s + 2.446 m/s² * 4.0 s ≈ 32.062 m/s

To convert this back to km/h:

v = 32.062 m/s * (3600 s/h) / (1000 m/km) ≈ 115.4 km/h

Two small, positively charged spheres have a combined charge of 5.0 x 10 -5 C. If each sphere is repelled from the other by an electrostatic force of 1.0 N when the spheres are 2.0 m apart, what is the charge, in micro-coulomb, on the sphere with the smaller charge?

Answers

Explanation:

It is given that,

Let q₁ and q₂ are two small positively charged spheres such that,

[tex]q_1+q_2=5\times 10^{-5}\ C[/tex].............(1)

Force of repulsion between the spheres, F = 1 N

Distance between spheres, d = 2 m

We need to find the charge on the sphere with the smaller charge. The force is given by :

[tex]F=k\dfrac{q_1q_2}{d^2}[/tex]

[tex]q_1q_2=\dfrac{F.d^2}{k}[/tex]

[tex]q_1q_2=\dfrac{1\ N\times (2\ m)^2}{9\times 10^9}[/tex]

[tex]q_1q_2=4.45\times 10^{-10}\ C[/tex]............(2)

On solving the system of equation (1) and (2) using graph we get,

[tex]q_1=0.0000384\ C=38.4\ \mu C[/tex]

[tex]q_2=0.0000116\ C=11.6\ \mu C[/tex]

So, the charge on the smaller sphere is 11.6 micro coulombs. Hence, this is the required solution.


Combined charge = 5.0 x 10-5 C
Distance between spheres = 2.0 m
Force = 1.0 N

Formula:
Coulomb's Law: F = k * (q1 * q2) / r2

Calculations:
q1 + q2 = 5.0 x 10-5 C (Given)
q1 = q2 - x (Assuming q2 is larger charge)
Substitute and solve for x

Answer:
The charge on the sphere with the smaller charge is 2.5 x 10-5 C or 25 micro-coulombs.

A heavier mass m1 and a lighter mass m2 are 19.0 cm apart and experience a gravitational force of attraction that is 9.20 x 10^-9 N in magnitude. The two masses have a combined value of 5.80 kg. Determine the value of each individual mass.

Answers

answers:

m2 = 1.05 kg and m1 = 4.75 kg

Explanation:

the gravitational force is given by:

             Fg = Gm1×m2/(r^2)

9.20×10^-9 = [(6.67×10^-11)×(m1×m2)]/[(19×10-2)^2]

    (m1×m2) = 4.98 kg^2

             m1 = 4.98/m2 kg

but we given that:

m1 + m2 = 5.80 kg

4.98/m2 + m2 = 5.80

4.98 + (m2)^2 = 5.80×m2

(m2)^2 - 5.80×m2 + 4.98 = 0

by solving the quadratic equation above:

m2 = 4.75 kg or m2 = 1.05 kg

due to that from the information, m2 has a lighter mass, then m2 = 1.05 kg.

then m1 = 5.80 - 1.05 = 4.75 kg.

If the absolute temperature of a gas is 600 K, the temperature in degrees Celsius is: A. 705°C. B. 873°C. C. 273°C. D. 327°C

Answers

Answer:

D). [tex]327 ^0 C[/tex]

Explanation:

As we know that temperature scale is linear so we will have

[tex]\frac{^0C - 0}{100 - 0} = \frac{K - 273}{373 - 273}[/tex]

now we have

[tex]\frac{^0 C - 0}{100} = \frac{K - 273}{100}[/tex]

so the relation between two scales is given as

[tex]^0 C = K - 273[/tex]

now we know that in kelvin scale the absolute temperature is 600 K

so now we have

[tex]T = 600 - 273 = 327 ^0 C[/tex]

so correct answer is

D). [tex]327 ^0 C[/tex]

An engineer weighs a sample of mercury (ρ = 13.6 × 10^3 kg/m^3 ) and finds that the weight of the sample is 7.8 N. What is the sample’s volume? The acceleration of gravity is 9.81 m/s^2 . Answer in units of m^3 .

Answers

Answer:

[tex]0.0000584637\ m^{3}\\[/tex]

Explanation:

Hello

Density is a measure of mass per unit of volume

[tex]d=\frac{m}{v} \\\\\\[/tex]

and the weight of an object is defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity

[tex]W=mg[/tex]

let

[tex]d=13.6*10^{3} \frac{kg}{m^{3} }  \\ W=7.8 N\\W=mg\\m=\frac{W}{g} \\m=\frac{7.8 N}{9.81 \frac{m}{s^{2} } }\\m=0.8 kg\\\\d=\frac{m}{v} \\v=\frac{m}{d} \\v=\frac{0.8 kg}{13.6*10^{3} \frac{kg}{m^{3} }}\\Volume=0.0000584637\ m^{3}[/tex]

the volumen of the sample is 0.0000584637 m3

have a great day

Suppose there is a pendulum with length 5m hanging from a ceiling. A ball of mass 2kg is attached is attached to the bottom of the pendulum. The ball begins at rest. If I give the ball a velocity of 6 m/s, what is the maximum height that the ball will achieve? Use the energy conservation model to solve, and assume that there is no friction or air resistance.

Answers

Answer:

1.84 m from the initial point (3.16 m from the ceiling)

Explanation:

According to the law of conservation of energy, the initial kinetic energy of the ball will be converted into gravitational potential energy at the point of maximum height.

Therefore, we can write:

[tex]\frac{1}{2}mv^2 = mg\Delta h[/tex]

where

m = 2 kg is the mass of the ball

v = 6 m/s is the initial speed of the ball

g = 9.8 m/s^2 is the acceleration due to gravity

[tex]\Delta h[/tex] is the change in height of the ball

Solving for [tex]\Delta h[/tex],

[tex]\Delta h = \frac{v^2}{2g}=\frac{6^2}{2(9.8)}=1.84 m[/tex]

So, the ball raises 1.84 compared to its initial height.

Therefore:

- if we take the initial position of the ball as reference point, its maximum height is at 1.84 m

- if we take the ceiling as reference point, the maximum height of the ball will be

5 m - 1.84 m = 3.16 m from the ceiling

The specific heat of a certain type of cooking oil is 1.75 J/(g⋅°C).1.75 J/(g⋅°C). How much heat energy is needed to raise the temperature of 2.34 kg2.34 kg of this oil from 23 °C23 °C to 191 °C?191 °C?

Answers

Answer:

Heat energy required = 687.96 kJ

Explanation:

Heat energy required, H = mCΔT.

Mass of cooking oil, m = 2.34 kg = 2340 g

Specific heat of cooking oil, C = 1.75 J/(g⋅°C)

Initial temperature = 23 °C

Final temperature = 191 °C

Change in temperature, ΔT = 191 - 23 = 168 °C

Substituting values

            H = mCΔT

            H = 2340 x 1.75 x 168 = 687960 J = 687.96 kJ

Heat energy required = 687.96 kJ

A rope exerts a 280 N force while pulling an 80 Kg skier upward along a hill inclined at 12o. The rope pulls parallel to the hill. The coefficient of friction between the skier and the hill is 0.15. If the skier starts from rest, determine her speed after moving 100 m up the slope.

Answers

Answer:

The speed of the skier after moving 100 m up the slope are of V= 25.23 m/s.

Explanation:

F= 280 N

m= 80 kg

α= 12º

μ= 0.15

d= 100m

g= 9,8 m/s²

N= m*g*sin(α)

N= 163 Newtons

Fr= μ * N

Fr= 24.45 Newtons

∑F= m*a

a= (280N - 24.5N) / 80kg

a= 3.19 m/s²

d= a * t² / 2

t=√(2*d/a)

t= 7.91 sec

V= a* t

V= 3.19 m/s² * 7.91 s

V= 25.23 m/s

12.1 Following data are given for a direct shear test conducted on dry sand: Specimen dimensions: diameter= 63 mm; height= 25 mm Normal stress: 150 kN/m2 Shear force at failure: 276 N a. Determine the angle of friction, φ’ b. For a normal stress of 200 kN/m2 , what shear force is required to cause failure?

Answers

Final answer:

The problem involves applying principles of soil mechanics to a direct shear test on a sand specimen. The calculations involve converting the specimen's physical dimensions to an area and applying formulas related to shear stress and friction angle.

Explanation:

The problem given is an application of soil mechanics principles in civil engineering. The situation is a direct shear test on a dry sand specimen. To answer this, we need to understand principles related to shearing force, shearing stress and their relationship with angle of internal friction (φ‘) and normal stress.

Shear stress can be calculated using the formula τ = F/A, where F is the force and A is the area over which the force is distributed. The area can be calculated based on the specimen's dimensions using A = πr² (where r is the radius of the specimen, which is half of the diameter). Given the normal stress and the shear stress, the angle of friction φ’ can be calculated using the formula tan(φ‘) = τ / σ, where σ is the normal stress.

To calculate the shear force required to cause failure under a different normal stress, we use the above formula in reverse, solving for τ (which represents the shear stress under the new normal stress), then multiply by the area to obtain the force. In other words, F = τA.

Please note that this is a simplified calculation ignoring potential complexities of real-world soil behavior.

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The angle of friction φ' is approximately 30.50°. For a normal stress of 200 kN/m², the required shear force to cause failure is approximately 367.97 N.

To determine the angle of friction (φ') and the required shear force at a different normal stress, we will conduct the following calculations:

a. Determining the angle of friction, φ’

Determine the cross-sectional area (A) of the specimen:

Diameter (d) = 63 mm = 0.063 m

Area (A) = π/4 × d² = (3.1416/4) × (0.063²) ≈ 0.003117 m²

Calculate the shear stress (τ) at failure:

τ = Shear Force (F) / Area (A)

F = 276 N

τ = 276 N / 0.003117 m² ≈ 88555.19 N/m² = 88.56 kN/m²

Calculate the angle of friction (φ'):

Normal stress (σ) = 150 kN/m²

The relationship between shear stress and normal stress in terms of the angle of friction (φ') is given by:

τ = σ × tan(φ')

88.56 kN/m² = 150 kN/m² × tan(φ')

tan(φ') = 88.56 / 150 ≈ 0.5904

φ' = atan(0.5904) ≈ 30.50°

b. For a normal stress of 200 kN/m², Shear Force required to cause failure:

Calculate the shear stress (τ) using the angle of friction:

σ = 200 kN/m²

τ = σ × tan(φ')

τ = 200 kN/m² × tan(30.50°) ≈ 118.08 kN/m²

Determine the required shear force (F):

τ = F / A

F = τ × A

F = 118.08 kN/m² × 0.003117 m² ≈ 367.97 N

Conclusion:

The angle of friction (φ') is approximately 30.50°.

The shear force required to cause failure at a normal stress of 200 kN/m² is approximately 367.97 N.

A square, single-turn coil 0.132 m on a side is placed with its plane perpendicular to a constant magnetic field. An emf of 27.1 mV is induced in the winding while the area of the coil decreases at a rate of 0.0785 m2 /s. What is the magnitude of the magnetic field? Answer in units of T.

Answers

Answer:

0.35 T

Explanation:

Side, a = 0.132 m, e = 27.1 mV = 0.0271 V, dA / dt = 0.0785 m^2 / s

Use the Faraday's law of electromagnetic induction

e = rate of change of magnetic flux

Let b be the strength of magnetic field.

e = dФ / dt

e = d ( B A) / dt

e = B x dA / dt

0.0271 = B x 0.0785

B = 0.35 T

Final answer:

The magnitude of the magnetic field is 3.45 × 10^-4 T.

Explanation:

The magnitude of the induced emf in a square, single-turn coil can be calculated using the equation: emf = -N * A * (d(B)/dt), where N is the number of turns, A is the area of the coil, and d(B)/dt is the rate of change of the magnetic field. In this case, the area of the coil is decreasing at a rate of 0.0785 m2/s, and the emf is given as 27.1 mV. We can rearrange the equation to solve for the magnitude of the magnetic field (B):

B = -emf / (N * d(A)/dt) = -27.1 mV / (1 * 0.0785 m2/s) = -345.222 T/s = 3.45 × 10^-4 T/s.

Therefore, the magnitude of the magnetic field is 3.45 × 10^-4 T.

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A cable applies a vertical force to a crate with a mass of 70.0 kg. It first lifts the crate to a height of 12.0 m above the floor, and then lowers it back to the floor. What is the total work done by the force?

Answers

Answer:

Answer to the Question:

Explanation:

In this case, the total work done by the cable is zero, since in the aforementioned problem, the work depends only on the starting and ending point, these two being equal. Keeping its gravitational potential energy equal.

Answer:

The total work done is zero.

Explanation:

Given;

mass of the crate, m = 70.0 kg

height above ground through which the crate is lifted, h = 12.0 m

The only work associated in lifting and lowering this crate is gravitational potential energy.

Potential Energy during lifting = - mgh

                                                  = - 70 x 9.8 x 12

                                                  = - 8232 J

Potential Energy during lowering = mgh

                                                       =  70 x 9.8 x 12

                                                       =  8232 J  

Total total work done by the force = - 8232 J + 8232 J  = 0

Therefore, the total work done is zero.

An electron is released from rest at the negative plate of a parallel plate capacitor and accelerates to the positive plate (see the drawing). The plates are separated by a distance of 1.5 cm, and the electric field within the capacitor has a magnitude of 2.5 x 106 V/m. What is the kinetic energy of the electron just as it reaches the positive plate?

Answers

Answer:

6 x 10⁻¹⁵ J

Explanation:

d = distance between the plates = 1.5 cm = 0.015 m

E = magnitude of electric field between the plates of the capacitor = 2.5 x 10⁶ V/m

q = magnitude of charge on the electron = 1.6 x 10⁻¹⁹ C

Force on the electron due to electric field is given as

F = q E

F = (1.6 x 10⁻¹⁹) (2.5 x 10⁶)

F = 4 x 10⁻¹³ N

KE₀ = initial kinetic energy of electron at negative plate = 0 J

KE = final kinetic energy of electron at positive plate = ?

Using work-change in kinetic energy

F d = KE - KE₀

(4 x 10⁻¹³) (0.015) = KE - 0

KE = 6 x 10⁻¹⁵ J

Final answer:

An electron released from rest towards the positive plate of a capacitor, which is separated by a distance of 1.5 cm and an electric field of 2.5 x 10^6 V/m, attains a kinetic energy of 37.5 keV when it reaches the positive plate.

Explanation:

The subject you're studying is called electrical potential energy, specifically its conversion into kinetic energy in the context of a parallel plate capacitor. In the case of an electron released from rest towards the positive plate of a capacitor, it is said to be moving through an electrical potential difference. This difference, coupled with the charge of the electron, provides the electron with energy, accelerating it.

Given that the electric field (E) is 2.5 x 106 V/m and the distance between the plates (d) is 1.5 cm or 0.015 m, we can use the formula E = V/d to calculate the potential difference (V). Substituting the given values, the potential difference is 2.5 x 106 V/m * 0.015 m = 37,500 V or 37.5 kV.

Furthermore, as per the relation that an electron accelerated through a potential difference of 1 V attains an energy of 1 electron-volt (eV), an acceleration through 37.5 kV will grant an energy of 37.5 keV. Since its initial kinetic energy was zero (as it was released from rest), this 37.5 keV is the kinetic energy of the electron just as it reaches the positive plate.

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An article states that the fission of 2.0 g of uranium−235 releases 6.8 × 108 kcal, the same amount of energy as burning two tons (4,000 lb) of coal. If this report is accurate, how much energy is released when 1.0 g of coal is burned?

Answers

Answer:

340 kcal

Explanation:

Energy released by 2 g of Uranium is same as the energy released by 2 tons of coal.

Energy given by 2 tons of coal = 6.8 x 10^8 kcal

Energy given by 2 x 10^6 g of coal = 6.8 x 10^8 kcal

Energy released by 1 g of coal = (6.8 x 10^8) / (2 x 10^6) = 340 kcal

Final answer:

To find the energy released by burning 1.0 g of coal, we need to determine the proportion of energy released by burning coal compared to uranium-235. By converting two tons of coal to grams and using the information that 2.0 g of uranium-235 releases 6.8 × 108 kcal, we calculate that approximately 374.6 kcal is released when 1.0 g of coal is burned.

Explanation:

To calculate the amount of energy released when 1.0 g of coal is burned, we need to compare it with the energy released by uranium-235. The article states that the fission of 2.0 g of uranium-235 releases 6.8 × 108 kcal, which is the equivalent of burning two tons (4,000 lb) of coal. Therefore, the energy released by burning 1.0 g of coal can be found using a simple proportion.

First, let’s convert two tons of coal to grams:

1 ton = 2,000 pounds (lb)2 tons = 4,000 lb1 lb = 453.592 grams4,000 lb = 4,000 × 453.592 grams

Now, we have the total grams of coal that release the same amount of energy as 2.0 g of uranium-235:

4,000 lb × 453.592 g/lb = 1,814,368 g of coal

Next, we can set up the proportion to solve for the energy released by 1.0 g of coal:

(6.8 × 108 kcal) / (1,814,368 g) = x kcal / (1 g)

By cross-multiplying and solving for x, we find that:

x = (6.8 × 108 kcal) / (1,814,368 g)

x ≈ 374.6 kcal/g

Therefore, about 374.6 kcal of energy is released when 1.0 g of coal is burned.

You need to make mashed potatoes, so you buy a 19 pound bag of Russet potatoes from the grocery store. To the nearest tenth of a kilogram, how many kilograms of potatoes are in the bag? Take a kilogram to be equivalent to 2.21 pounds.

Answers

Answer:

8.6 kg

Explanation:

According to the question,

1 Kg = 2.21 pound

2.21 pound = 1 kg

1 pound = 1 / 2.21 kg

19 pound = 19 / 2.21 kg = 8.59 kg

By rounding to nearest tenth, it is equal to 8.6 kg.

If a display has a dynamic range of 20 dB and the smallest voltage it can handle is 200 mV, then the largest voltage it can handle is_________V.

a. 20

b. 2.0

c. 0.2

d. 0.02

Answers

Answer:

The largest voltage is 0.02 V.

(d) is correct option.

Explanation:

Given that,

Range = 20 dB

Smallest voltage = 200 mV

We need to calculate the largest voltage

Using formula of voltage gain

[tex]G_{dB}=10 log_{10}(\dfrac{V_{out}^2}{V_{in}^{2}})[/tex]

[tex]20 =10 log_{10}(\dfrac{V_{out}^2}{V_{in}^{2}})[/tex]

[tex]2=log_{10}(\dfrac{V_{out}^2}{V_{in}^{2}})[/tex]

[tex]10^2=\dfrac{V_{out}^2}{V_{in}^{2}}[/tex]

[tex]\dfrac{V_{out}}{V_{in}^}=10[/tex]

[tex]V_{in}=\dfrac{V_{out}}{10}[/tex]

[tex]V_{in}=\dfrac{200}{10}[/tex]

[tex]V_{in}=20\ mV[/tex]

[tex]V_{in}=0.02\ V[/tex]

Hence, The largest voltage is 0.02 V.

Final answer:

The largest voltage a display with a dynamic range of 20 dB can handle, when the smallest voltage is 200 mV, is 2.0 V.

Explanation:

If a display has a dynamic range of 20 dB and the smallest voltage it can handle is 200 mV, then the largest voltage it can handle can be calculated using the formula for decibels: 20 log(V1/V0), where V1 is the unknown voltage and V0 is the reference voltage, in this case, 200 mV. The dynamic range in decibels represents a ratio of the largest to smallest voltage it can handle.


To find the largest voltage (V1) the equation can be rewritten as V1 = V0 * 10^(dB/20). So, V1 = 200 * 10^(20/20) = 200 * 10 = 2000 mV or 2.0 V. Therefore, the correct answer is b. 2.0.

An object moves uniformly around a circular path of radius 23.5 cm, making one complete revolution every 1.95 s. (a) What is the translational speed of the object? (b) What is the frequency of motion in hertz? (c) What is the angular speed of the object?

Answers

Explanation:

a)

The circumference of the path is:

C = 2πr

C = 2π (0.235 m)

C = 1.48 m

Velocity = displacement / time

v = 1.48 m / 1.95 s

v = 0.757 m/s

b)

1 rev / 1.95 s = 0.513 Hz

c)

1 rev / 1.95 s × (2π rad / rev) = 3.22 rad/s

(a) The translational speed of the object is 0.76 m/s.

(b) The frequency of the object's motion is 0.51 Hz.

(c) The angular speed of the object is 3.22 rad/s.

Angular speed of the object

The angular speed of the object is calculated as follows;

ω = 1 rev/ 1.95 s = 0.51 rev/s

ω =  0.51 rev/s x 2π rad

ω = 3.22 rad/s

Angular frequency of the object

The frequency of the object's motion is determined from the angular speed as shown below;

ω = 2πf

f = ω/2π

f = (3.22)/2π

f = 0.51 Hz

Translational speed of the object

The translational speed of the object is calculated as follows;

v = ωr

v = 3.22 x 0.235

v = 0.76 m/s

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A 0.500 kg piece of granite is heated 21.5 °C by a sitting in the sun and thereby absorbs 8.5 kcal of heat. What is the specific heat of the granite rock?

Answers

Answer:

Specific heat of the granite rock = 3387.05 Jkg⁻¹°C⁻¹

Explanation:

We have heat required, H = mcΔT

Mass of granite, m = 0.500 kg

Specific heat of granite, c = ?

Change in temperature, ΔT = 21°C

Heat energy, H = 8.5 kcal = 8500 x 4.184 = 35564 J

Substituting

         H = mcΔT

         35564 = 0.500 x c x 21

          c = 3387.05 Jkg⁻¹°C⁻¹

Specific heat of the granite rock = 3387.05 Jkg⁻¹°C⁻¹

At a certain location close to Earth's surface, we observe a uniform electric field of magnitude 105 N/C directed straight down. What must be the charge (in C) that needs to be placed on a person of mass 81 kg in order to make them lose contact with the ground? Make sure to correctly identify the sign of the charge needed.

Answers

Answer:

- 7.56 C

Explanation:

E = 105 N/C downwards

m = 81 kg

Let the charge on the man is q.

To lose te contact with the ground, the electrostatic foece should be balanced by the weight of the person.

The charge should be negative in nature so that the direction of electrostatic force is upwards and weight is downwards.

q E = m g

q = (81 x 9.8) / 105 = 7.56 C

You hold a slingshot at arm's length, pull the light elastic band back to your chin, and release it to launch a pebble horizontally with speed 150 cm/s. With the same procedure, you fire a bean with speed 1050 cm/s. What is the ratio of the mass of the bean to the mass of the pebble?

Answers

Answer:

[tex]\frac{m_2}{m_1} = 0.020[/tex]

Explanation:

As we know that in this sling shot the kinetic energy given to the mass is equal to the elastic potential energy stored in it

now we shot two object in same sling shot so here the kinetic energy must be same in two objects

[tex]\frac{1}{2}m_1v_1^2 = \frac{1}{2}m_2v_2^2[/tex]

now we have

[tex]m_1[/tex] = mass of pebble

[tex]m_2[/tex] = mass of bean

[tex]v_1 = 150 cm/s[/tex]

[tex]v_2 = 1050 cm/s[/tex]

now we have

[tex]\frac{m_2}{m_1} = \frac{v_1^2}{v_2^2}[/tex]

[tex]\frac{m_2}{m_1} = \frac{150^2}{1050^2}[/tex]

[tex]\frac{m_2}{m_1} = 0.020[/tex]

Final answer:

The velocities of the bean and pebble launched from the slingshot can be related to their masses under the assumption of equal elastic potential energy. However, a numerical ratio of the masses can't be provided without additional data.

Explanation:

Given that the procedure of launching both the pebble and the bean is the same, we assume that the same amount of elastic potential energy is converted into kinetic energy in both cases. By the formula for kinetic energy, K.E.= 1/2 mv^2, where m is the mass and v is the velocity, we can equate the kinetic energy of the two projectiles and use the known velocities to solve for the ratio of the masses. However, it's necessary to understand that without the masses or some other missing variables (such as the elasticity of the slingshot or air resistance), we cannot provide a numerical ratio of the bean to the pebble's mass. This question is mainly about the principles of energy conversion and the conservation of mechanical energy.

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The pressure of 4.20 L of an ideal gas in a flexible container is decreased to one-third of its original pressure, and its absolute temperature is decreased by one-half. What is the final volume of the gas?

Answers

Answer:

6.30 L

Explanation:

P1 = P, V1 = 4.20 L, T1 = T

P2 = P/3, V2 = ?, T2 = T/2

Where, V2 be the final volume.

Use ideal gas equation

[tex]\frac{P_{1}\times V_{1}}{T_{1}} = \frac{P_{2}\times V_{2}}{T_{2}}[/tex]

[tex]V_{2} = \frac{P_{1}}{P_{2}}\times\frac{T_{2}}{T_{1}}\times V_{1}[/tex]

By substituting the values, we get

V2 = 6.30 L

A 180-g block is pressed against a spring of force constant 1.35 kN/m until the block compresses the spring 10.0 cm. The spring rests at the bottom of a ramp inclined at 60.0° to the horizontal. Using energy considerations, determine how far up the incline the block moves from its initial position before it stops under the following conditions.

Answers

Answer:

L = 4.32 m

Explanation:

Here we can use the energy conservation to find the distance that it will move

As per energy conservation we can say that the energy stored in the spring = gravitational potential energy

[tex]\frac{1}{2}kx^2 = mg(L + x)sin\theta[/tex]

[tex]\frac{1}{2}(1.35 \times 10^3)(0.10^2) = (0.180)(9.8)(L + 0.10)sin60[/tex]

now we need to solve above equation for length L

[tex]6.75 = 1.53(L + 0.10)[/tex]

[tex]L + 0.10 = 4.42[/tex]

[tex]L = 4.42 - 0.10[/tex]

[tex]L = 4.32 m[/tex]

Final answer:

The question involves calculating the distance a block moves up an incline after compressing a spring, using conservation of energy. It requires converting spring potential energy into gravitational potential energy and solving for the distance using trigonometry and principles of physics.

Explanation:

The question involves using energy considerations to determine how far up an incline a block moves before it stops. Initially, the block compresses a spring, converting mechanical energy into spring potential energy. This potential energy is then converted back into kinetic energy and finally into gravitational potential energy as the block moves up the incline. To calculate the distance, we use the conservation of energy principle, equating the spring potential energy at the beginning to the gravitational potential energy at the point where the block stops moving up the incline.

Given: mass of the block (m) = 180 g = 0.18 kg, spring constant (k) = 1.35 kN/m = 1350 N/m, compression distance (x) = 10.0 cm = 0.1 m, angle of incline (\(\theta\)) = 60.0\u00b0.

The spring potential energy (\(U_s\)) can be calculated using the formula \(U_s = \frac{1}{2}kx^2\). The gravitational potential energy (\(U_g\)) when the block has moved up the incline is given by \(U_g = mgh\), where h is the height above the initial position, which can be related to the distance along the incline (d) through trigonometry considering the angle of incline.

By setting \(U_s = U_g\) and solving for d, we find the distance d the block moves up the incline before stopping. This involves algebraic manipulation and application of trigonometric identities to relate height to distance on an incline.

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