Question 1

A cyclist (A) is moving at 2.0 m/s relative to the ground. A train (B) moves at 3.0 m/s in the same direction, and a passenger (P) walks inside the train at 1.0 m/s in the same direction as the train. What is the velocity of the passenger relative to the cyclist?

Accepted Answer

$$v_{P/A} = 4.0\ \mathrm{m/s}$$

Question 2

Which of the following best describes the direction of the normal force exerted by a wall on a picture frame pressed against it?

Accepted Answer

To the left (perpendicular to the wall, away from the frame)

Question 3

A block slides down a rough incline. Which free body diagram correctly shows the directions of the normal force, friction force, and weight?

Accepted Answer

Normal force perpendicular to the surface, friction force up the incline, weight vertically downward

Question 4

A crate with mass $$20.0\ \mathrm{kg} is $$pulled with a rope by a force of $$100.0\ \mathrm{N} at an $$angle of $$30.0^{\circ}$$ above the horizontal. The crate moves with constant velocity. What is the magnitude of the friction force acting on the crate?

Accepted Answer

$$f = 86.6\ \mathrm{N}$$

Question 5

Which of the following is the correct vector equation for Newton’s Second Law?

Accepted Answer

$$\sum_i \vec{F}_i = m\vec{a}$$

Question 6

A stalled car is being pushed up a hill at constant velocity by three people. What is the net force on the car?

Accepted Answer

Zero

Question 7

A block of mass $$m is $$hanging from a rope and is at rest. Which of the following is true about the forces acting on the block?

Accepted Answer

The tension force is equal to the weight

Question 8

A person pulls a 6.00 kg crate connected by a rope to a 4.00 kg crate on a frictionless surface. How does the net force acting on crate 1 compare to that acting on crate 2?

Accepted Answer

$$F_2$$ = $$F_1$$ 
eq 0$$

Question 9

Which of the following statements about Newton’s First Law is correct?

Accepted Answer

An object at rest will remain at rest unless acted upon by an external force

Question 10

A block of mass $$m is $$falling freely under gravity. What is the net force acting on the block?

Accepted Answer

$$\vec{F}_{net} = m\vec{a}$$, where $$\vec{a} = \vec{g}$$

Question 11

A motorcycle and a truck both experience the same net force. Which will have the greater acceleration?

Accepted Answer

The motorcycle, because it has less mass

Question 12

Which of the following is NOT a type of force commonly encountered in mechanics?

Accepted Answer

Magnetic force

Question 13

A block is pulled to the right with a rope and moves at constant velocity on a horizontal surface. Which statement is true about the forces acting on the block?

Accepted Answer

The tension force is equal to the friction force

Question 14

Which of the following is the correct SI unit for force?

Accepted Answer

N

Question 15

A spring exerts a force $$F_s on a $$block of mass $$m$$ when stretched or compressed. In which direction does the spring force act?

Accepted Answer

Opposite to the direction of displacement

Question 16

A constant net force acts on an object in the negative y-direction. Which of the following best describes the object's motion?

Accepted Answer

Acceleration of the object is in the $$-y$$ direction

Question 17

Which of the following is a correct statement of Newton’s Third Law?

Accepted Answer

For every force, there is an equal and opposite reaction force

Question 18

A book rests on a hand. Which free-body diagram correctly represents the forces acting on the book?

Accepted Answer

Upward force from the hand and downward weight

Question 19

Which of the following is true about inertial reference frames?

Accepted Answer

Newton’s laws are valid only in inertial reference frames

Question 20

A block of mass $$m is at $$rest on a horizontal surface. Which of the following equations correctly represents the equilibrium of forces acting on the block?

Accepted Answer

$$N = mg$$

Newton’s Laws of Motion and Forces: Structured Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드