Question 1

Which of the following best describes Newton's First Law of Motion?

Accepted Answer

An object will remain at rest or move with constant velocity unless acted upon by a net external force.

Question 2

A 3.1 kg cat is lying on a table. What is the magnitude of the gravitational force (weight) acting on the cat? Use $$g = 9.8\ \mathrm{m/s^2$}.$$

Accepted Answer

$$30.4\ \mathrm{N}$$

Question 3

Which of the following statements about velocities and accelerations is correct?

Accepted Answer

Velocities are relative, but accelerations are absolute.

Question 4

A 10 kg box is at rest on a horizontal surface. If the coefficient of static friction between the box and the surface is $$\mu_s = 0.5$$, what is the maximum force that can be applied horizontally before the box starts to move? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$49\ \mathrm{N}$$

Question 5

A car is moving at a constant velocity on a straight road. Which of the following must be true?

Accepted Answer

The net force acting on the car is zero.

Question 6

A 5 kg block is pulled across a horizontal surface with a constant velocity by a horizontal force of $$20\ \mathrm{N}. $$What is the coefficient of kinetic friction between the block and the surface? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$0.41$$

Question 7

Which of the following is an example of Newton's Third Law?

Accepted Answer

A swimmer pushes water backward, and the water pushes the swimmer forward.

Question 8

A 2 kg object is suspended by a rope and is at rest. What is the tension in the rope? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$19.6\ \mathrm{N}$$

Question 9

A 1.5 kg block is released from rest on a frictionless incline at an angle $$	heta = 30^\circ. $$What is the acceleration of the block down the incline? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$4.9\ \mathrm{m/s^2$}$$

Question 10

A 0.5 kg ball is dropped from rest and reaches terminal velocity as it falls through the air. Which of the following is true at terminal velocity?

Accepted Answer

The drag force equals the weight of the ball.

Question 11

A 4 kg block is at rest on a horizontal surface. If a horizontal force of $$15\ \mathrm{N} is $$applied and the coefficient of kinetic friction is $$\mu_k = 0.3$$, what is the acceleration of the block? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$0.45\ \mathrm{m/s^2$}$$

Question 12

Which of the following best describes an inertial reference frame?

Accepted Answer

A reference frame moving at constant velocity where the laws of physics are identical.

Question 13

A 6 kg object is pulled by a horizontal force of $$30\ \mathrm{N} on a $$surface with a coefficient of kinetic friction $$\mu_k = 0.2. $$What is the net acceleration of the object? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$2.1\ \mathrm{m/s^2$}$$

Question 14

A 2 kg block is at rest on a 20° incline. What is the normal force acting on the block? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$18.4\ \mathrm{N}$$

Question 15

A 1 kg object is moving at a constant velocity on a horizontal surface. Which of the following statements is true?

Accepted Answer

The net force acting on the object is zero.

Question 16

A 0.5 kg puck slides on ice with a coefficient of kinetic friction $$\mu_k = 0.05. $$What is the frictional force acting on the puck? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$0.245\ \mathrm{N}$$

Question 17

A 2 kg block is pushed up a frictionless incline at $$30^\circ$$ with a force of $$20\ \mathrm{N}$$ parallel to the incline. What is the acceleration of the block? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$5.1\ \mathrm{m/s^2$}$$

Question 18

A 1 kg object is dropped from rest and falls through air. As its speed increases, what happens to the drag force acting on it?

Accepted Answer

The drag force increases with speed.

Question 19

A 3 kg block is at rest on a horizontal surface. If the maximum static friction force is $$15\ \mathrm{N}$$, what is the coefficient of static friction? (Use $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$0.51$$

Applying Newton's Laws: Forces, Equilibrium, and Friction

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