Question 1

A 70.0 kg running back is moving north at 5.00 m/s and collides with an 80.0 kg linebacker moving west at 4.00 m/s. After they stick together, what is the magnitude of their velocity immediately after the collision?

Accepted Answer

$$2.98\ \mathrm{m/s}$$

Question 2

A 4.00 kg bomb at rest explodes into three pieces. Piece 1 (1.00 kg) flies north at 20.0 m/s, Piece 2 (1.50 kg) flies east at 16.0 m/s. What is the magnitude of the velocity of Piece 3 immediately after the explosion?

Accepted Answer

$$12.8\ \mathrm{m/s}$$

Question 3

A block slides from rest down a frictionless ramp and then across a rough horizontal surface until it stops. According to the work-energy theorem, which statement is correct?

Accepted Answer

The net work done on the block equals its change in kinetic energy.

Question 4

A 0.300 kg block is dropped from 0.800 m onto a spring with $$k = 500\ \mathrm{N/m}. $$What is the maximum compression $$x of $$the spring?

Accepted Answer

$$0.170\ \mathrm{m}$$

Question 5

A bullet of mass $$8.00\ \mathrm{g}$$ traveling at $$350\ \mathrm{m/s}$$ embeds in a $$2.00\ \mathrm{kg}$$ block at rest on a $$1.50\ \mathrm{m}$$ high table. What is the speed of the block and bullet immediately after the collision?

Accepted Answer

$$1.39\ \mathrm{m/s}$$

Question 6

A monatomic ideal gas ($$C_v = \frac{3R}{2}$$ per mole) undergoes an isochoric heating from $$T_1 = 300$$\ \mathrm{K}$$, p_1$ = 1.00 	imes 10^5$\ \mathrm{Pa}$$, $$V = 0.0200\ \mathrm{m}^3 to$$ $$p_2 = 3.00$$ 	imes $$10^5$$\ \mathrm{Pa}$$. What is the final temperature after this step?

Accepted Answer

$$900\ \mathrm{K}$$

Question 7

A spring is stretched by a distance $$x$$ and has potential energy $$U. If it is $$stretched by $$3x$$, what is the new potential energy?

Accepted Answer

$$9U$$

Question 8

A heat pump moves heat from a cold to a warm reservoir. Which statement is correct?

Accepted Answer

This process is possible only if external work is done on the system.

Question 9

A piston compresses $$0.500$$ mol of ideal gas from $$V_1 = 10.0$$\ \mathrm{L}$$ to V_2$ = 2.50\ \mathrm{L} at $$constant $$T = 350\ \mathrm{K}. $$What is the work done ON the gas during this compression?

Accepted Answer

$$2870\ \mathrm{J}$$

Question 10

A $$0.500\ \mathrm{kg}$$ copper block at $$200\ ^\circ\mathrm{C} is $$dropped into $$2.00\ \mathrm{kg} of $$water at $$20.0\ ^\circ\mathrm{C} in an $$insulated container. What is the final equilibrium temperature?

Accepted Answer

$$23.2\ ^\circ\mathrm{C}$$

Question 11

A monatomic ideal gas undergoes a cyclic process. Which of the following is true about the net work done by the gas over one complete cycle?

Accepted Answer

It equals the net heat absorbed by the gas over the cycle.

Question 12

A block slides from rest down a frictionless ramp of height $$h$$ and then across a rough horizontal surface until it stops. If the coefficient of kinetic friction is $$\mu_k$$, what is the distance $$d$$ the block travels on the rough surface before stopping?

Accepted Answer

$$d = \frac{h}{\mu_k g}$$

Question 13

A $$0.200\ \mathrm{kg}$$ sample of ice at $$-20.0\ ^\circ\mathrm{C} is $$converted to steam at $$130\ ^\circ\mathrm{C}. $$Which stage requires the most energy?

Accepted Answer

Boiling the water at $$100\ ^\circ\mathrm{C}$$

Question 14

A roller coaster car of mass $$850\ \mathrm{kg}$$ starts from rest at $$h = 30.0\ \mathrm{m} on a $$frictionless track with a loop of radius $$R = 7.50\ \mathrm{m} ($$bottom at ground). What is the speed at the top of the loop?

Accepted Answer

$$19.2\ \mathrm{m/s}$$

Question 15

A system of two particles has zero total momentum. Which must be true?

Accepted Answer

The particles' momenta are equal in magnitude and opposite in direction.

Question 16

An ideal gas has its pressure doubled at constant temperature. What happens to its volume?

Accepted Answer

It is halved.

Question 17

Which best explains why the root-mean-square (rms) speed of gas molecules increases with temperature?

Accepted Answer

Temperature is a direct measure of average molecular kinetic energy.

Question 18

A projectile (no air resistance) has minimum kinetic energy at which point?

Accepted Answer

At the highest point, where the vertical velocity component is zero.

Question 19

When catching a fast ball, moving your hands backward as you catch it:

Accepted Answer

Increases stopping time, reducing average force on your hands.

Physics 2010 Exam 3 Practice: Step-by-Step Guidance

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