Q: A block of mass $$m_2$$ slides down a frictionless incline of angle $$\theta$$ connected by a cord to a hanging mass $$m_1. $$What is the acceleration of the system?

$$a = \frac{m_2$ g \sin \theta}{m_1$ + m_2$}$$

Q: A block of mass $$m is $$sliding down a frictionless incline of angle $$\theta. $$What is the component of gravitational force parallel to the incline?

$$F_{\parallel} = m g \sin \theta$$

Question 1

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

Accepted Answer

An object at rest will remain at rest, and an object in motion will continue moving with constant velocity unless acted upon by a net force.

Question 2

A 10 kg box is at rest on a frictionless surface. A constant force of 20 N is applied horizontally. What is the acceleration of the box?

Accepted Answer

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

Question 3

Which of the following is NOT a fundamental force in physics?

Accepted Answer

Frictional

Question 4

A person weighing 600 N on Earth travels to the Moon, where the gravitational acceleration is $$g_{Moon} = \frac{1}{6}g_{Earth}. $$What is their weight on the Moon?

Accepted Answer

$$100\ \mathrm{N}$$

Question 5

In the Atwood machine, two masses $$m_1$$ and $$m_2$$ ($$m_2$$ \u003e $$m_1) $$are connected by a string over a frictionless pulley. What is the acceleration of the system?

Accepted Answer

$$a = \frac{(m_2$ - m_1$)g}{m_1$ + m_2$}$$

Question 6

A block of mass $$m is $$pulled across a horizontal surface with a constant velocity. Which statement is true about the forces acting on the block?

Accepted Answer

The net force on the block is zero.

Question 7

Which equation correctly expresses Newton's Second Law in three dimensions?

Accepted Answer

$$\sum F_{NET,x} = m a_x,\ \sum F_{NET,y} = m a_y,\ \sum F_{NET,z} = m a_z$$

Question 8

A 125 N object hangs from two cables making angles $$\$$theta_1$$ = 37^\circ$$ and $$\$$theta_2$$ = 53^\circ$$ with the horizontal. What is the tension in the cable at $$53^\circ$$?

Accepted Answer

$$T_2 = 99.9$$\ \mathrm{N}$$

Question 9

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

Accepted Answer

A swimmer pushes water backward and moves forward.

Question 10

Two blocks of masses $$m_1$$ and $$m_2$$ are in contact on a frictionless surface. A force $$F is $$applied to $$m_1. $$What is the acceleration of the system?

Accepted Answer

$$a = \frac{F}{m_1$ + m_2$}$$

Question 11

A block of mass $$m_2$$ slides down a frictionless incline of angle $$	heta$$ connected by a cord to a hanging mass $$m_1. $$What is the acceleration of the system?

Accepted Answer

$$a = \frac{m_2$ g \sin 	heta}{m_1$ + m_2$}$$

Question 12

Which of the following is true about mass and weight?

Accepted Answer

Mass is an inherent property, weight depends on gravitational acceleration.

Question 13

A block of mass $$m is at $$rest on a table. What is the normal force acting on the block?

Accepted Answer

$$n = m g$$

Question 14

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

Accepted Answer

The object moves with constant velocity or remains at rest.

Question 15

A block of mass $$m is $$pulled by a force $$F on a $$rough surface. The block moves at constant velocity. What is the magnitude of the frictional force?

Accepted Answer

$$f = F$$

Question 16

Which of the following is a contact force?

Accepted Answer

Frictional force

Question 17

A block of mass $$m is $$suspended by a cable. If the block is at rest, what is the tension in the cable?

Accepted Answer

$$T = m g$$

Question 18

In the Atwood machine, if $$m_1$$ = $$m_2$$, what is the acceleration of the system?

Accepted Answer

$$a = 0$$

Question 19

A block of mass $$m is $$sliding down a frictionless incline of angle $$	heta. $$What is the component of gravitational force parallel to the incline?

Accepted Answer

$$F_{\parallel} = m g \sin 	heta$$

Newton's Laws of Motion: Principles, Applications, and Problem Solving

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