1. Which of the following are the units for the spring constant, k?

(A) kg · m²/s²
(B) kg · s²
(C) kg · m/s
(D) kg/s²

2. Which of the following is an expression for mechanical power?

(A) Ft/m
(B) F²m/a
(C) Fm²/t
(D) F²t/m

3. A pendulum consisting of a mass m attached to a light string of length ℓ is displaced from its rest position, making an angle θ with the vertical. It is then released and allowed to swing freely. Which of the following expressions represents the velocity of the mass when it reaches its lowest position?

4. An engine maintains constant power on a conveyor belt machine. If the belt’s velocity is doubled, the magnitude of its average acceleration

(A) is doubled
(B) is quartered
(C) is halved
(D) is quadrupled

5. A mass m is moving horizontally along a nearly frictionless floor with velocity v. The mass now encounters a part of the floor that has a coefficient of kinetic friction given by µ. The total distance traveled by the mass before it is slowed by friction to a stop is given by

(A) 2v²/µg
(B) v²/2µg
(C) 2mgv²
(D) mv²/2g

6. Two unequal masses are dropped simultaneously from the same height. The two masses will experience the same change in

(A) acceleration
(B) kinetic energy
(C) potential energy
(D) velocity

7. A pendulum that consists of a 2-kg mass swings to a maximum vertical displacement of 17 cm above its rest position. At its lowest point, the kinetic energy of the mass is equal to

(A) 0.33 J
(B) 3.33 J
(C) 33.3 J
(D) 333 J

8. A 0.3-kg mass rests on top of a spring that has been compressed by 0.04 m. Neglect any frictional effects, and consider the spring to be massless. Then, if the spring has a constant k equal to 2,000 N/m, to what height will the mass rise when the system is released?

(A) 1.24 m
(B) 0.75 m
(C) 0.54 m
(D) 1.04 m

9. A box is pulled along a smooth floor by a force F, making an angle θ with the horizontal. As θ increases, the amount of work done to pull the box the same distance, d,|

(A) increases
(B) increases and then decreases
(C) remains the same
(D) decreases

10. As the time needed to run up a flight of stairs decreases, the amount of work done against gravity

(A) increases
(B) decreases
(C) remains the same
(D) increases and then decreases

1. A 0.75-kg sphere is dropped through a tall column of liquid. When the sphere has fallen a distance of 2.0 m, it is observed to have a velocity of 5 m/s.

(a) How much work was done by the frictional “viscosity” of the liquid?

(b) What is the average force of friction during the displacement of 2.0 m?

2. A 15-kg mass is attached to a massless spring by a light string that passes over a frictionless pulley as shown below. The spring has a force constant of 500 N/m and is unstretched when the mass is released. What is the velocity of the mass when it has fallen a distance of 0.3 m?

3. A 1.5-kg block is placed on an incline. The mass is connected to a massless spring by means of a light string passed over a frictionless pulley, as shown below. The spring has a force constant k equal to 100 N/m. The block is released from rest, and the spring is initially unstretched. The block moves down a distance of 16 cm before coming to rest. What is the coefficient of kinetic friction between the block and the surface of the incline?

4. Explain how it might be possible for a moving object to possess, and simultaneously not possess, kinetic energy?

5. When you hold up a 10-kg mass with your arms outstretched, you get tired. However, according to physics, you have not done any work! Explain how this is possible.

6. A car (1200 kg) is traveling up a steep incline (35 degrees with the horizontal) at a speed of 25 MPH. How much power is required?