LESSON 4: Unit 2: Forces and Energy Module 1: Forces and Motion Lesson 4 - Gravitational Force

Question 1

Which of the following best describes balanced forces?

a) Forces that cause a change in the motion of an object
b) Forces that are equal in magnitude and opposite in direction.
c) Forces that act in the same direction and cause acceleration
d) Forces that act on an object only in one direction

Answer 1

Forces that are equal in magnitude and opposite in direction.

Question 2

Which of the following is an example of a non-contact force?
a) Tension
b) Friction
c) Gravitational force
d) Air resistance

Answer 2

Gravitational force.

Question 3

Gravitational force depends on:
a) The size of the objects only
b) The mass of the objects and the distance between them
c) The temperature of the objects
d) The color of the objects

Answer 3

The mass of the objects and the distance between them.

Question 4

What happens to the gravitational force between two objects if their masses are doubled?
a) It stays the same
b) It is halved
c) It is quadrupled
d) It is doubled

Answer 4

It is quadrupled.

Question 5

What happens when unbalanced forces act on an object?
a) The object stays at rest
b) The object moves with constant speed
c) The object accelerates
d) The object experiences no change in motion

Answer 5

The object accelerates.

Question 6

Which of the following is true about mass and weight?
a) Mass is the same everywhere, but weight varies
depending on the gravitational pull
b) Mass and weight are the same thing
c) Weight is constant, but mass changes depending on the location
d) Mass changes depending on the gravitational pull, but weight is constant

Answer 6

Mass is the same everywhere, but weight varies depending on the gravitational pull.

Question 7

How is the gravitational force on the Moon compared to that on Earth?
a) It is much stronger on the Moon
b) It is much weaker on the Moon
c) It is the same on the Moon as on Earth
d) It is stronger on Earth than on the Moon

Answer 7

d) It is stronger on Earth than on the Moon

Question 8

Which of the following is NOT an example of a non-contact force?
a) Gravitational force
b) Magnetic force
c) Frictional force
d) It is stronger on Earth than on the Moon

Answer 8

Frictional force.

Question 9

An object has a mass of 50 kg on Earth. What would its weight be on the earth?
a) 500 N
b) 50 kg
c) 80 N
d) 10 N

Answer 9

500 N.

Question 10

What happens to the gravitational force between two objects if the distance between them increases?
a) The gravitational force increases
b) The gravitational force decreases
c) The gravitational force remains the same d) The gravitational force becomes zero

Answer 10

The gravitational force decreases.

Question 11

1. Define gravitational force

Answer 11

The force of attraction that pulls two objects toward each other, caused by their masses and the distance between them

Question 12

2. Define a non contact force

Answer 12

● The force that one object can apply to another object without touching it.

Question 13

3. Define field

Answer 13

● A region of space that has a physical quantity(such as a force) at every point.

Question 14

4.Define Weight

Answer 14

● The gravitational force exerted on an object.

Question 15

5. Define Mass

Answer 15

● Mass is the amount of matter in an object.

Question 16

1. List 2 examples of non contact forces

Answer 16

● Gravitational force
● Magnetic force

Question 17

2. List 2 examples of contact forces

Answer 17

● Frictional force
● Tension force

Question 18

3. List 2 factors that affect the strength of the gravitational force.

Answer 18

● The mass of the objects
● The distance between the objects

Question 19

1- Compare and contrast contact forces and non-contact forces.

Answer 19

Contact forces
● Require physical contact
between objects to exert
force.
● (e.g.Friction, tension,
normal force, applied force,
air resistance.

Both
● Both affect the motion or
behavior of objects.

Non-contact forces.
● Can exert force without
any physical contact, can
act from a distance
● (e.g., gravity or
magnetism).

Question 20

2- Compare and contrast gravitational force and magnetic force.

Answer 20

Gravitational force
● Always an attractive
force; it never repels.

Both
● Both are non contact
forces acting from a
distance

Magnetic force.
● Can be attractive or
repulsive depending on
the polarity of the magnets
or the charge of particles.

Question 21

3- Compare and contrast mass and weight.

Answer 21

Mass
● Mass does not change
with location, whether on
Earth, the Moon, or in
space

Both
● they are both properties
that describe the matter in
an object and are
measurable quantities

Weight
● Weight changes based on
the gravitational pull at the
object’s location.

Question 22

4- Compare and contrast the effect of gravitational force on Earth and on the Moon.

Answer 22

Gravitational force on Earth
● Stronger, about 9.8 m/s2,
pulls objects down more
strongly, leading to greater
weight

Both
● The gravitational force on
both Earth and the Moon
affects the weight of
objects

Gravitational force on Moon
● Weaker, about 1.6 m/s2,
results in lighter objects

Question 23

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

Answer 23

Newton’s Second Law of Motion: F=m×a
Where:
● F is the force applied (250 N),
● m is the mass (which we need to find),
● a is the acceleration (5 N/Kg)
Rearranging the formula to solve for m:
m=F/ a
m= 250 N/ 5 N/Kg
M= 50 kg
So, the mass of the object is 50 kg.

Question 24

2. A car with a mass of 1,500 kg is driven by a force of 3,000 N. The driver steps on the gas pedal, and the car accelerates.
   What is the acceleration of the car?

Answer 24

F=m×a
a=F/m
a=3,000 N / 1,500 kg=2 m/s^2.
Answer: The acceleration of the car is 2 m/s^2.

Question 25

3. A truck with a mass of 2,000 kg is being driven and accelerates at a rate of 3 m/s2. What is the total force acting on the truck?

Answer 25

Using Newton's Second Law: F=m×a F=2,000 kg×3 m/s2=6,000 N Answer: The force acting on the truck is 6,000 N.

Question 26

4. Two students are investigating the effect of forces on the motion of an object. The two students each push on a box, as shown in the picture. Even though the students are pushing the box hard, the box does not move. Explain how the students could make the box move. STUDENT A -->[ ] <--- STUDENT B

Answer 26

● One student could push on the box with less force than the other student. This way the forces are not balanced, and the box will move in the direction of the push that has more force. ● OR a third student could help push the box from either side. This way the forces are not balanced, and the box will move in the direction of the push that has more force. ● OR both students could push the box from the same side. This way the forces are not balanced, and the box will move in the direction of the push.

Question 27

5. This diagram shows three models that represent the gravitational force, F, between objects. Make a claim about the effect of mass on the gravitational force between objects. Support your claim with evidence from the models. MODEL 1: MASS = X 0--> F <---0 MASS = X MODEL 2: MASS = X 0--> 2F <---0 MASS = 2X MODEL 3: MASS = 2X 0--> 4F <---0 MASS = 2X

Answer 27

Gravitational force increases as the mass of the objects increases. The model shows the gravitational force increased from F to 2F when the mass of one object increased from X to 2X. The model also shows the gravitational force increased from F to 4F when the mass of both objects increased from X to 2X