Newton's Laws of Motion Answers

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5

Rahul sits in a chair reading a book. Which force is equal to the force Rahul exerts on Earth?

A
Rahul’s weight
B
Rahul's mass
C
the sum of the weights of Rahul and the book
D
the sum of the weights of the chair, Rahul, and the book
6

Juan inflates a balloon and then releases its end to let the balloon go free as air comes out. The balloon then flies around the room.

A
According to Newton’s first law of motion, the balloon would stay still unless a force caused it to move.
B
According to Newton’s third law of motion, the balloon is pushed forward as the air is forced out.
C
According to Newton’s third law of motion, the balloon resists any change of motion unless an unbalanced force acts upon it.
D
According to Newton’s second law of motion, the balloon exerts a force on the air, which exerts a force back on the balloon.
8

How do Newton’s laws of motion explain why it is important to keep the ice smooth on a hockey rink so that players can pass a puck as quickly as possible?

A
Smooth ice reduces the inertia of the hockey puck.
B
Smooth ice increases the force used to accelerate the hockey puck.
C
Smooth ice reduces the unbalanced forces that would slow the hockey puck.
D
Smooth ice decreases the reaction force that the ice exerts on the hockey puck.
11

According to Newton’s first law of motion, when will an object at rest begin to move?

A
when its inertia decreases to zero
B
when an unbalanced force acts upon it
C
when the action and reaction forces are equal
D
when two equal and opposite forces act upon it
12

What is the mass of a crate if a force of 200 N causes it to accelerate at 8 m/s2? (Formula: F=ma)

A
25 kg
B
192 kg
C
208 kg
D
16 kg
13

Two people push on the same door from opposite sides as shown.

Question illustration
A
both people exert the same force so that the forces are unbalanced.
B
neither person exerts a force on the door so that the net force is zero.
C
one person exerts more force than the other so that the forces are unbalanced.
D
both people exert the same force so that the forces are balanced.
14

Laura sees a horse pulling a buggy.Which statement best describes the forces acting on the horse and buggy?

A
The net forces exerted on the horse and cart are the same, but the action force is larger.
B
The net forces exerted on the horse and cart are the same, but they are in the same direction.
C
The net forces exerted on the horse and cart are not the same, so the two forces cancel out.
D
The net forces exerted on the horse and cart are not the same, so they are not balanced forces.
15

A force of 5 N accelerates an object. The object’s mass is 50 g. What is the acceleration of the object? (Formula: F=ma)

A
0.01 m/s2
B
0.1 m/s2
C
10 m/s2
D
100 m/s2
16

A bowling ball has a mass of 7.2 kg and a weight of 70.6 N. It moves down the bowling alley at 1 m/s and strikes a pin with a force of 15.0 N. What is the force that the pin exerts on the bowling ball?

A
7.2 N
B
15.0 N
C
70.6 N
D
85.6 N
17

Juan inflates a balloon and then releases its end to let the balloon go free as air comes out. The balloon then flies around the room.

A
According to Newton’s first law of motion, the balloon would stay still unless a force caused it to move.
B
According to Newton’s third law of motion, the balloon is pushed forward as the air is forced out.
C
According to Newton’s third law of motion, the balloon resists any change of motion unless an unbalanced force acts upon it.
D
According to Newton’s second law of motion, the balloon exerts a force on the air, which exerts a force back on the balloon.
18

How do Newton’s laws of motion explain why it is important to keep the ice smooth on a hockey rink so that players can pass a puck as quickly as possible?

A
Smooth ice reduces the inertia of the hockey puck.
B
Smooth ice increases the force used to accelerate the hockey puck.
C
Smooth ice reduces the unbalanced forces that would slow the hockey puck.
D
Smooth ice decreases the reaction force that the ice exerts on the hockey puck.
19

A ball has a mass of 140 g. What is the force needed to accelerate the ball at 25 m/s2? (Formula: F=ma)

A
3.5 N
B
115 N
C
165 N
D
4.5 N

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