Question 1

A 5 kg box is pulled across a horizontal surface with a constant velocity by a force of 20 N applied at an angle of 30° above the horizontal. What is the magnitude of the frictional force acting on the box?

Accepted Answer

$$20 \ \mathrm{N}$$

Question 2

A car moves in a horizontal circle of radius $$50 \ \mathrm{m} at a $$constant speed of $$20 \ \mathrm{m/s}. $$What is the magnitude of the car's acceleration?

Accepted Answer

$$8 \ \mathrm{m/s^2$}$$

Question 3

A projectile is launched horizontally from a $$45 \ \mathrm{m}$$ high cliff with an initial speed of $$15 \ \mathrm{m/s}. $$How far from the base of the cliff does the projectile land? (Assume $$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$30.6 \ \mathrm{m}$$

Question 4

Which of the following best describes the work done by gravity on a ball thrown straight up into the air and caught at the same height?

Accepted Answer

The work done by gravity is zero.

Question 5

A $$2 \ \mathrm{kg}$$ object is moving at $$10 \ \mathrm{m/s}. $$What is its kinetic energy?

Accepted Answer

$$100 \ \mathrm{J}$$

Question 6

A rollercoaster car of mass $$500 \ \mathrm{kg} is at $$the top of a $$30 \ \mathrm{m}$$ hill. What is its gravitational potential energy relative to the bottom of the hill? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$147,000 \ \mathrm{J}$$

Question 7

A block slides down a frictionless incline of height $$h. If it $$starts from rest, what is its speed at the bottom?

Accepted Answer

$$\sqrt{2gh}$$

Question 8

A $$3 \ \mathrm{kg}$$ object is attached to a string and swung in a vertical circle of radius $$2 \ \mathrm{m}. $$What is the minimum speed at the top of the circle to keep the string taut? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$4.43 \ \mathrm{m/s}$$

Question 9

A force of $$10 \ \mathrm{N}$$ acts on a $$2 \ \mathrm{kg}$$ object for $$5 \ \mathrm{s}. $$What is the change in velocity of the object?

Accepted Answer

$$5 \ \mathrm{m/s}$$

Question 10

A ball is thrown upward with an initial velocity of $$20 \ \mathrm{m/s}. $$How long does it take to reach its maximum height? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$2.04 \ \mathrm{s}$$

Question 11

A $$1 \ \mathrm{kg}$$ puck slides on a frictionless surface at $$3 \ \mathrm{m/s}$$ and collides with a stationary $$2 \ \mathrm{kg}$$ puck. If they stick together, what is their final velocity?

Accepted Answer

$$1 \ \mathrm{m/s}$$

Question 12

Which of the following statements about centripetal force is correct?

Accepted Answer

Centripetal force is the net force directed toward the center of a circular path.

Question 13

A $$0.5 \ \mathrm{kg}$$ ball is attached to a string and swung in a horizontal circle of radius $$1.5 \ \mathrm{m} at a $$speed of $$4 \ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

$$5.33 \ \mathrm{N}$$

Question 14

A $$10 \ \mathrm{kg}$$ box is at rest on a horizontal surface. The coefficient of static friction between the box and the surface is $$0.4. $$What is the minimum force required to start moving the box? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$39.2 \ \mathrm{N}$$

Question 15

A student pushes a $$2 \ \mathrm{kg}$$ box up a $$30^\circ$$ incline at constant speed. If the incline is $$5 \ \mathrm{m}$$ long and friction is negligible, how much work does the student do?

Accepted Answer

$$49 \ \mathrm{J}$$

Question 16

Which of the following is NOT a correct application of Newton's Second Law?

Accepted Answer

An object at rest must have a net force acting on it.

Question 17

A $$0.2 \ \mathrm{kg}$$ ball is dropped from a height of $$10 \ \mathrm{m}. $$What is its speed just before hitting the ground? ($$g = 9.8 \ \mathrm{m/s^2$})$$

Accepted Answer

$$14 \ \mathrm{m/s}$$

Question 18

A $$1 \ \mathrm{kg}$$ object moves in a circle of radius $$0.5 \ \mathrm{m} at$$ $$2 \ \mathrm{m/s}. $$What is the magnitude of the net force acting on the object?

Accepted Answer

$$8 \ \mathrm{N}$$

Question 19

A $$0.5 \ \mathrm{kg}$$ puck slides on ice with a velocity of $$6 \ \mathrm{m/s}$$ and comes to rest after $$3 \ \mathrm{s}$$ due to friction. What is the magnitude of the friction force?

Accepted Answer

$$1 \ \mathrm{N}$$

Question 20

A $$2 \ \mathrm{kg}$$ object is moving in a circle of radius $$4 \ \mathrm{m} at a $$constant speed of $$8 \ \mathrm{m/s}. $$What is the required centripetal force?

Accepted Answer

$$32 \ \mathrm{N}$$

Physics Study Guide: Forces, Kinematics, Circular Motion, and Work & Energy

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