$$a = \frac{F_{\text{net}}}{m} = \frac{10\ \text{N}}{2\ \text{kg}} = 5\ \text{m/s}^2$$

$$\text{Average speed} = \frac{\text{total distance}}{\text{total time}}$$

$$a = \frac{20\ \text{m/s}}{4\ \text{s}} = 5\ \text{m/s}^2$$

Question 1

Which of the following best describes Galileo's concept of inertia?

Accepted Answer

Objects in motion remain in motion unless acted upon by an external force.

Question 2

A 2 kg object is pushed with a net force of 10 N. What is its acceleration?

Accepted Answer

$$a = \frac{F_{	ext{net}}}{m} = \frac{10\ 	ext{N}}{2\ 	ext{kg}} = 5\ 	ext{m/s}^2$$

Question 3

Which of the following is a vector quantity?

Accepted Answer

Force

Question 4

A crate is pushed across a floor at constant speed. If the applied force is 50 N, what is the force of friction?

Accepted Answer

50 N

Question 5

If you stand on two bathroom scales and your weight is evenly distributed, each scale reads 300 N. What is your total weight?

Accepted Answer

600 N

Question 6

A car rounds a curve at constant speed. Which statement is true?

Accepted Answer

The car is accelerating because its direction is changing.

Question 7

Which equation correctly expresses average speed?

Accepted Answer

$$	ext{Average speed} = \frac{	ext{total distance}}{	ext{total time}}$$

Question 8

A bowling ball is at rest on a table. Which of the following statements is true?

Accepted Answer

The support force equals the weight of the ball.

Question 9

A 1 kg object weighs 10 N on Earth. What is its weight on the Moon, where gravity is about 1/6th that of Earth?

Accepted Answer

1.67 N

Question 10

Which of the following best describes the force of friction?

Accepted Answer

It always acts to oppose motion.

Question 11

A net force of 0 N acts on a moving object. What can you conclude about the object's motion?

Accepted Answer

It moves with constant velocity.

Question 12

A car accelerates from rest to 20 m/s in 4 seconds. What is its acceleration?

Accepted Answer

$$a = \frac{20\ 	ext{m/s}}{4\ 	ext{s}} = 5\ 	ext{m/s}^2$$

Question 13

A free-falling object has a speed of 30 m/s at one instant. What will its speed be exactly 2 seconds later? (Assume $$g = 10\ 	ext{m/s}^2)$$

Accepted Answer

50 m/s

Question 14

Which of the following is true about the density of a 1 kg block of iron on the Moon compared to on Earth?

Accepted Answer

It is the same on the Moon.

Question 15

A cart is pushed to the right with a force of 15 N and pulled to the left with a force of 20 N. What is the net force and its direction?

Accepted Answer

5 N to the left

Question 16

Which of the following best describes dynamic equilibrium?

Accepted Answer

An object moving at constant velocity with zero net force.

Question 17

A bee hovers above a flower in a 5 m/s breeze. What must the bee do to remain stationary relative to the flower?

Accepted Answer

Fly at 5 m/s into the breeze.

Question 18

Which of the following statements about acceleration is correct?

Accepted Answer

Acceleration is the rate at which velocity changes with time.

Question 19

If a falling object gains 10 m/s each second it falls, what is its acceleration?

Accepted Answer

$$10\ 	ext{m/s}^2$$

Question 20

The distance fallen by a free-falling body each second:

Accepted Answer

Increases each second.

Patterns of Motion and Equilibrium: Foundations of Classical Mechanics

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