Chapter 5: Newton's Third Law of Motion

Question 1

The force of the surface that acts on an object perpendicular to the surface is known as the

Answer 1

Normal force

Question 2

An object rests on the ramp that is angled at 20 degrees above the horizontal. What direction (relative to the vertical) will the force of gravity point?

Answer 2

The gravitational force will be directed exactly downward, along the vertical

Question 3

Consider the car driving at a constant speed on a level road. Which of the following is an action reaction pari (from Newton’s Third Law)

Answer 3

The normal force exerted on the car by the road and the downward force exerted on the road by the car

Question 4

Imagine a car sitting empty in the parking lot. Which of the following is the most complete list of the forces that belong on a free-body diagram of the car?

Answer 4

The normal force on your car by the pavement it rests on and the force of gravity on your car by the Earth

Question 5

The upward reaction force on the blades of a helicopter is called the:

Answer 5

Lift Force

Question 6

Josh punches his open left hand with his right hand. Which statement is true about the force his two hands exert on each other?

Answer 6

Josh’s right hand and left hand exert equal and opposite forces on each other

Question 7

Floating in deep space, you find yourself at rest next to a small asteroid. You reach out and tap the asteroid with a hammer. What happens to you in this process?

Answer 7

You will briefly accelerated away from the asteroids and then drift away at a constant speed

Question 8

At a person is standing still while leaning against the wall in a classroom. Which is the best answer regarding the numbers of forces exerted on her?

Answer 8

At least four

Question 9

To define the position of an object in a plane, you need to measure

Answer 9

The object’s distance from a reference point and its angle measured from a reference line

Question 10

Miguel leans against a wall. Which statement is true about the forces Miguel and the wall exert on each other?

Answer 10

Miguel and the wall exert equal and opposite forces on each other

Question 11

In which case would the normal force acting on a 200 N boy be the greatest

Answer 11

When the boy is standing on a flat surface

Question 12

Jack and Luis are pushing on opposite ends of a shopping cart. At the moment, the cart is staying at rest. We know that the force each person exert on the cart are equal in magnitude and opposite in direction. What is the reason this must be true?

Answer 12

Newton’s second law tell us these two forces must be equal and opposite

Question 13

Which of the following is true?

Answer 13

The Earth and the Moon attract one another with a force of equal magnitude

Question 14

Allision pulls her little brother, Brody, in a sled on a snow-covered path at a constant speed. Which of the following is an action-reaction pair (from Newton’s Third Law)

Answer 14

The pulling force that Allision exert on the sled and the pulling force that the sled exerts on Allision

Question 15

In a tug-of-war contest, what determines the winner?

Answer 15

Whichever team pushes on the ground with more force.

Question 16

Newton’s Third Law is commonly referred to as:

Answer 16

Action-reaction

Question 17

As you accelerate upward in an elevator, which force exerted on you has the greatest magnitude?

Answer 17

The normal force from the elevator floor pushing up on you

Question 18

Imagine standing in an elevator that is moving upward. Which of the following is the most complete list of the forces that belong on your FBD in that moment?

Answer 18

The normal force on you by the elevator floor and the force of gravity on you by the Earth

Question 19

Michael leans on a shopping cart, causing it to start moving. Which statement is true about the forces Michael and the cart exert on each other?

Answer 19

Michael and the cart exert equal and opposite forces on each other

Question 20

A box rests on a table. The normal force exerted by the table on the box in equal in magnitude to the weight of the box and points in the opposite directions. This is because

Answer 20

The net force on the box is zero and therefore, the forces must be balanced

Question 21

An object rests on a ramp that is angled at 20 degrees above the horizontal. What direction (relative to the vertical) will the normal force from the ramp point?

Answer 21

The normal force will be directed 20 degrees to the right of vertical

Question 22

While the sparring, Katie punches Arman in the shoulder. Which statement is true about the force Katie and Arman exert on each other?

Answer 22

Katie exert a force on Arman’s shoulder and Arman exerts a force on Katie’s hands

Question 23

1. A tablecloth being quickly pulled away leaving the place setting at rest

Answer 23

Newton’s First Law

Question 24

2. A shopping cart getting harder to push as it fills up with groceries

Answer 24

Newton’s Second Law

Question 25

3. Tires pushing the road backward, the road pushing the car forward

Answer 25

Newton’s Third Law