LESSON 3: Unit 2: Energy and motion Module 1: Force and Motion Lesson 2 - Force and Acceleration

Question 1

What is a force that resists the sliding motion of two surfaces that are touching?
a. friction
b. noncontact force
c. Gravity
d. acceleration

Answer 1

Friction

Question 2

What is the sum of all the forces acting on an object?
a. noncontact force
b. gravity
c. net force
d. friction

Answer 2

Net force

Question 3

Choose the correct answer to find the net force: 20 N to the left, and another 10 newtons to the right.
a. 45N to the Right
b. 15 N Right
c. 10 N Left
d. 45 N Left

Answer 3

10 N Left

Question 4

What is a simple model that can help you understand the forces acting on an object?
a. net force
b. vector
c. reference point
d. free-body diagram

Answer 4

Free-body diagram

Question 5

What is a force that one object can apply to another object without touching it?
a. normal force
b. friction
c. contact force.
d. noncontact force

Answer 5

Noncontact force

Question 6

What is an attractive force that exists between all objects that have mass?
a. normal force
b. contact force.
c. friction
d. Gravity

Answer 6

Gravity

Question 7

Choose the correct answer to find the net force: 30 N to the left, and another 15 newtons to the right.
a. 45N to the Right
b. 15 N Right
c. 15 N Left
d. 45 N Left

Answer 7

15 N Left

Question 8

Two people are pulling on a chain in opposite directions with forces of 500 N and 600 N. The forces would best be described as ____.
a. Balanced forces
b. Unbalanced forces
c. Gravitational force
d. Action - reaction forces

Answer 8

Unbalanced forces

Question 9

_________________ states that an object in motion will stay in motion and an object at rest will stay at rest unless acted on by a force.
a. Newton’s first law of motion
b. Newton’s second law of motion
c. Newton’s third law of motion

Answer 9

Newton’s first law of motion

Question 10

The law that says ______ it represents Newton’s 1st law.
a. That the force F acting on a body is equal to the mass m of the body multiplied by the acceleration a of its center of mass, F = ma, is the basic equation of motion in classical mechanics.
b. That an object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
c. That for every action (force) in nature there is an equal and opposite reaction.

Answer 10

That an object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.

Question 11

Define Newton’s first law

Answer 11

Newton’s first Law states that an object in motion will stay in motion and an object at rest will stay at rest unless acted upon by a force.

Question 12

Define a force

Answer 12

A force is a push or a pull on an object.

Question 13

Define Friction

Answer 13

Friction is the force that resists the sliding motion of two surfaces that are touching.

Question 14

Define acceleration

Answer 14

Acceleration is a measure of the change in velocity during a period of time.

Question 15

Define net force

Answer 15

The net force is the sum of all forces acting on an object.

Question 16

1- List the factors that determine the effect of a force on an object.

Answer 16

●Mass
● Acceleration

Question 17

2- List three real-life examples of Newton’s First Law of Motion.

Answer 17

● Seatbelt in a Car
● A Book on a Table
● A Ball Rolling on the Ground

Question 18

3- List three situations where friction is helpful.

Answer 18

● Walking
● Braking in a Car
● Writing with a Pen or Pencil

Question 19

4- List three examples of balanced forces in everyday life.

Answer 19

● A Book Resting on a Table
● A Car Cruising at a Constant Speed
● A Person Standing Still

Question 20

5- List three examples of unbalanced forces in motion.

Answer 20

● A Car Accelerating
● A Falling Object
● Kicking a Soccer Bal

Question 21

1. Compare and contrast balanced and unbalanced forces.

Answer 21

Balanced Force
●No change in motion,
resulting in constant
velocity or no motion at all
(net force is zero)
Both
● Both Affect Motion
● Both follow Newton’s Laws
Unbalanced force
● Causes a change in motion
(acceleration or
deceleration), as the net
force is not zero..

Question 22

2. Compare and contrast Newton’s First and Second Laws of Motion.

Answer 22

Newton’s First Law of Motion.

● An object will remain at
rest or in uniform motion
unless acted upon by an
external force.
● The First Law talks about
when an object does not
change its motion

Both
● Both laws focus on
explaining how forces
affect an object’s motion
● Both laws rely on the concept of external forces acting on an object

Newton’s Second Law of Motion.
● The acceleration of an
object depends on the net
force acting on it and its
mass.
●the Second Law focuses
on how the motion of an
object changes when
forces are applied
.

Question 23

3. Compare and contrast mass and weight in terms of forces.

Answer 23

Mass

● Mass is a measure of how much matter is in an object
● Measured in kilograms (kg) or grams (g).
● Mass remains the same no
matter where you are

Both
● Mass and weight are
related to the amount of
matter in an object
●Mass and weight are
directly proportional to
each other

WEIGHT
● weight is a force that
depends on the mass and
gravitational pull.
● Measured in newtons (N)
● Weight changes depending
on the location (e.g., it’s
less on the Moon than on
Earth).

Question 24

Illustrate and label a diagram of balanced forces

Answer 24

• REFER TO PAGE 20 - Q1A

Question 25

2. Illustrate and label a diagram of unbalanced forces.

Answer 25

- REFER TO PAGE 20 - Q2A

Question 26

3. Illustrate and label a force diagram showing net force.

Answer 26

- REFER TO PAGE 21 - Q3A

Question 27

1. Describe how Newton’s First Law applies to objects in motion.

Answer 27

Newton's First Law states that an object in motion will stay in motion at a constant speed and direction unless acted upon by an external force. For example, a moving car will keep going until friction or brakes stop it.

Question 28

2. Describe how friction can either help or hinder movement.

Answer 28

● Friction can help movement by providing grip, like when shoes prevent slipping. It can hinder movement by slowing down or stopping motion, like when a car's brakes use friction to stop.

Question 29

3. Describe what happens when balanced forces act on an object.

Answer 29

When balanced forces act on an object, it remains at rest or continues moving at a constant speed in a straight line.

Question 30

4. Describe the relationship between force, mass, and acceleration.

Answer 30

The relationship is described by Newton's Second Law: Force equals mass times acceleration (F=ma). This means that the greater the mass, the less the acceleration for the same force, and the greater the force, the more the acceleration.

Question 31

5. Describe what happens when unbalanced forces act on an object

Answer 31

When unbalanced forces act on an object, they cause a change in motion. The object may speed up, slow down, change direction, start moving, or stop, depending on the direction of the force. This happens because unbalanced forces create a net force

Question 32

1. A boy is trying to pull a dog on a leash. The dog and the boy are moving in the same direction. a) Explain which force is greater, the boy or the dog and why. b) Are these forces balanced? Explain

Answer 32

a) Explain which force is greater, the boy or the dog and why. ● The dogs force is greater as the boy is moving toward the same direction as the dog b) Are these forces balanced? Explain ● No, as the net force is not zero.

Question 33

2. The classes are playing tug of war. Mrs. Williams’s homeroom pulls with a force of 50 N. Ms. Jones’s homeroom pulls with a force of 45 N in the opposite direction. a) What is the net force and direction? 45N <--[ ] --> 50N b) Who won? c) Is it balance or unbalanced force?

Answer 33

a) What is the net force and direction? Net force = 50N - 45N = 5N to the right b) Who won? ● Mrs. Williams’s homeroom. c) Is it balance or unbalanced force? ● Unbalanced as the net force does not equal zero.

Question 34

3. A force of 250 N applied to an object that accelerates at a rate of 5 N/Kg. Calculate the mass of the object

Answer 34

MASS = FORCE/ACCELERATION OR M= F/A = 250/5 = 50kg

Question 35

4. You are pushing a shopping cart at avenues mall in Kuwait with a force of 40 N. The cart has a mass of 20 kg. a. Calculate the acceleration of the cart. b. The shopping cart's mass increases to 40 kg (due to items inside). The cart is now moving at an acceleration of 1 m/s/s. Calculate the force you should apply on the cart.

Answer 35

a. Calculate the acceleration of the cart. ● Answer: A=F/M = 40/20 = 2m/s^2 b. The shopping cart's mass increases to 40 kg (due to items inside). The cart is now moving at an acceleration of 1 m/s/s. Calculate the force you should apply on the cart. F = MA = 40 X 1 = 40N

Question 36

5. A traveler at Kuwait International Airport is pushing a suitcase with a force of 65 N. However, the friction between the suitcase wheels and the floor creates a force of 15 N in the opposite direction. The suitcase has a mass of 25 kg. 15N to the right --> <---65N to the left a. Calculate the net force acting on the suitcase. b. Kuwait International Airport is designed with smooth floors to reduce friction and help travelers move their luggage more easily. Explain why you think airports avoid rough flooring inside terminals? c. Using Newton’s Second Law, calculate the acceleration of the suitcase.

Answer 36

a. Calculate the net force acting on the suitcase. Fnet = F applied = Friction Fnet = 65N - 15N = 50N b. Kuwait International Airport is designed with smooth floors to reduce friction and help travelers move their luggage more easily. Explain why you think airports avoid rough flooring inside terminals? ● Smooth floors reduce friction, making it easier for travelers to move suitcases and walk without resistance. This improves efficiency and comfort in busy areas. c. Using Newton’s Second Law, calculate the acceleration of the suitcase. A = Fnet/M = 50N / 25 k = 2m/s^2