Q: A 1 kg object weighs 10 N on Earth. What would its weight be on the Moon, where $$g = 1.6\ \mathrm{m/s}^2$$?

$$W = mg = 1 \times 1.6 = 1.6\ \mathrm{N}$$

Question 1

A 5 kg box is pushed across a horizontal floor with a force of 20 N to the right. If friction is ignored, what is the acceleration of the box?

Accepted Answer

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

Question 2

Which of the following statements best describes inertia?

Accepted Answer

The resistance of an object to changes in its motion

Question 3

A car and a bicycle are both at rest. You apply the same force to each. Which will have the greater acceleration, and why?

Accepted Answer

The bicycle, because it has less mass

Question 4

A 10 kg object is falling through the air and reaches terminal velocity. Which of the following is true at this moment?

Accepted Answer

The force of gravity equals the force of air resistance

Question 5

If you push a heavy crate and it does not move, which force is balancing your push?

Accepted Answer

Static friction

Question 6

A 2 kg object is acted on by a net force of 8 N. What is its acceleration?

Accepted Answer

$$a = \frac{F}{m} = \frac{8}{2} = 4\ \mathrm{m/s}^2$$

Question 7

Which of the following is NOT true about friction between solid surfaces?

Accepted Answer

Friction depends on the area of contact between surfaces

Question 8

A 1 kg object weighs 10 N on Earth. What would its weight be on the Moon, where $$g = 1.6\ \mathrm{m/s}^2$$?

Accepted Answer

$$W = mg = 1 	imes 1.6 = 1.6\ \mathrm{N}$$

Question 9

A truck and a car are both moving at the same speed. Which has more inertia and why?

Accepted Answer

The truck, because it has more mass

Question 10

If the net force on an object is zero, which of the following must be true?

Accepted Answer

The object moves at constant velocity or remains at rest

Question 11

A skydiver jumps from a plane and eventually reaches a constant speed. What is this speed called, and why does it occur?

Accepted Answer

Terminal velocity, because air resistance equals gravity

Question 12

Which of the following best explains why a wide tire does not increase friction compared to a narrow tire, assuming the weight is the same?

Accepted Answer

Friction does not depend on the area of contact

Question 13

A 3 kg object is pushed with a net force of 12 N. If the same force is applied to a 6 kg object, what happens to the acceleration?

Accepted Answer

It becomes half as much

Question 14

Which equation correctly relates force, mass, and acceleration according to Newton’s Second Law?

Accepted Answer

$$F = ma$$

Question 15

A person pushes a box across the floor at a steady speed. Which of the following is true about the forces acting on the box?

Accepted Answer

The applied force equals the friction force

Question 16

Which of the following is a correct statement about mass and weight?

Accepted Answer

Mass is the amount of matter; weight is the force of gravity on that matter

Question 17

A 4 kg object is acted on by a net force of 20 N. What is its acceleration, and what would the acceleration be if the mass doubled but the force stayed the same?

Accepted Answer

Initial: $$a = \frac{20}{4} = 5\ \mathrm{m/s}^2$$; If mass doubles: $$a = \frac{20}{8} = 2.5\ \mathrm{m/s}^2$$

Question 18

Which of the following best describes why it is harder to start sliding a heavy crate than to keep it moving?

Accepted Answer

Static friction is greater than sliding friction

Question 19

A person pulls a string attached to a heavy ball hanging from the ceiling. If the string is pulled slowly, which string breaks and why?

Accepted Answer

The top string breaks because it supports the weight of the ball

Question 20

Which of the following is true about fluid friction (such as air resistance)?

Accepted Answer

It increases as the speed of the object increases

Newton's Second Law of Motion: Force, Mass, and Acceleration

Study Guide - Practice Questions

Study Guide - Flashcards