Q: A 5 kg object is on the surface of the Earth. What is its weight? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

$$w = m \times g = 5\ \mathrm{kg} \times 9.8\ \mathrm{m/s^2$} = 49\ \mathrm{N}$$

Q: If the acceleration due to gravity on the Moon is $$1.62\ \mathrm{m/s^2$}$$, what would be the weight of a 10 kg object on the Moon?

$$w = 10\ \mathrm{kg} \times 1.62\ \mathrm{m/s^2$} = 16.2\ \mathrm{N}$$

Question 1

Which of the following scenarios best illustrates a field force rather than a contact force?

Accepted Answer

A magnet attracting a piece of iron from a distance

Question 2

Which fundamental force is responsible for holding atomic nuclei together, and what is its relative strength compared to gravity?

Accepted Answer

Strong nuclear force; it is much stronger than gravity

Question 3

According to Newton's First Law, what will happen to an object moving with constant velocity if the net external force acting on it is zero?

Accepted Answer

It will continue moving with constant velocity

Question 4

A 10 kg box is at rest on a frictionless surface. If a constant force of 20 N is applied horizontally, what is the acceleration of the box? Use Newton's Second Law.

Accepted Answer

$$a = \frac{F}{m} = \frac{20\ \mathrm{N}}{10\ \mathrm{kg}} = 2\ \mathrm{m/s^2$}$$

Question 5

Which of the following statements about mass and weight is correct?

Accepted Answer

Weight depends on location, but mass does not

Question 6

The gravitational force between two objects of masses $$m_1$$ and $$m_2$$ separated by a distance $$r is $$given by which equation?

Accepted Answer

$$F_g = G \frac{m_1$ m_2$}{r^2$}$$

Question 7

A 5 kg object is on the surface of the Earth. What is its weight? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$w = m 	imes g = 5\ \mathrm{kg} 	imes 9.8\ \mathrm{m/s^2$} = 49\ \mathrm{N}$$

Question 8

If the acceleration due to gravity on the Moon is $$1.62\ \mathrm{m/s^2$}$$, what would be the weight of a 10 kg object on the Moon?

Accepted Answer

$$w = 10\ \mathrm{kg} 	imes 1.62\ \mathrm{m/s^2$} = 16.2\ \mathrm{N}$$

Question 9

Which of the following best describes Newton's Third Law?

Accepted Answer

For every action, there is an equal and opposite reaction acting on different objects

Question 10

A woman pushes a man on ice with a force of $$85.0\ \mathrm{N}. If $$the man has a mass of $$75.0\ \mathrm{kg}$$, what is his acceleration?

Accepted Answer

$$a = \frac{85.0}{75.0} = 1.13\ \mathrm{m/s^2$}$$

Question 11

Which of the following is NOT a valid assumption when applying Newton's Laws in introductory mechanics problems?

Accepted Answer

Rotational motion must always be considered

Question 12

In a free body diagram, which forces should be included?

Accepted Answer

Only the forces acting directly on the object of interest

Question 13

A block of mass $$m is $$placed on an inclined plane at angle $$	heta. $$What is the component of gravitational force acting parallel to the incline?

Accepted Answer

$$mg \sin 	heta$$

Question 14

Which of the following statements about inertia is correct?

Accepted Answer

Inertia is the tendency of an object to resist changes in its motion

Question 15

If two objects interact, which statement about the forces they exert on each other is true according to Newton's Third Law?

Accepted Answer

The forces are equal in magnitude and opposite in direction

Question 16

A TV rests on a table. Which of the following is the correct action-reaction pair?

Accepted Answer

The normal force the table exerts on the TV and the normal force the TV exerts on the table

Question 17

Which of the following is a correct statement about external and internal forces?

Accepted Answer

External forces result from interactions between the object and its environment

Question 18

Which SI unit is used to measure force, and how is it defined in terms of base units?

Accepted Answer

Newton (N); $$1\ \mathrm{N} = 1\ \mathrm{kg} \cdot \mathrm{m}/\mathrm{s}^2$$

Chapter 4: The Laws of Motion – Classical Mechanics and Newton’s Laws

Study Guide - Practice Questions

Study Guide - Flashcards