Topic 1 Lesson 3 Forces and Motion

Forces and Motion

Students will identify the forces acting on an object.

Let's review!

Get ready for some vocabulary review.

Multiple Choice

The location of an object is its

• position

• magnet

• force

• push

Multiple Choice

the amount of space between two objects or places

• speed

• position

• distance

• weight

Multiple Choice

a change in position

• position

• magnet

• speed

• motion

A force is a push or a pull.

Force

A push could be something as difficult as moving a heavy boulder.
Or a push could be an action as simple as closing the classroom door.

Can you think of any other examples of a push?

​​Push

Some examples of a pull could be opening the door, pulling a wagon, or pulling your chair away from your desk.

Can you think of any other examples of a pull?

​​Pull

Exert means to apply strength or effort.

When you apply force, even the tiniest amount of force, to push or pull an object, you are exerting energy.

Exert

Let's pretend you're golfing, and the hole is about 3 feet in front of you. Can you control how hard or how soft you hit the golf ball with your club?
How do you control it?


Show me how you would hit the ball if the hole was right in front of you.

Now let's pretend you're golfing, and the hole is far away from you.
How do you control how far the ball goes?


Show me how you would hit the ball if the hole was right in front of you.

You would use a greater amount of force if you had to hit the ball hard. Therefore, because you used a greater force, the ball would go further.



The amount of force that is used can change the motion of an object.

Forces can make objects start moving, speed up, slow down, stop moving, or change direction.

Multiple Choice

A push or a pull is ____________.

• magnet

• speed

• force

• motion

Multiple Choice

Forces can change the motion of object.

• True

• False

Multiple Choice

Forces can make objects start moving, speed up, slow down, stop moving, or change direction.

• True

• False

Types of forces

Contact Forces Noncontact Forces
(when objects are touching) (when forces act on an object at a distance)

1. Tension force 1. Gravity
2. Spring force 2. Magnetism
3. Friction 3. Electricity

Multiple Choice

There's only one kind of force.

• True

• False

A pulling force that stretches something

Examples:
- Pulling a rubber band
-Plucking guitar strings
- A swing on a playground

Tension Force

Happens after an object has been stretched. It springs back to its original position.

Examples:
- Letting go of a stretched rubber band
-Trampoline
- Pogo sticks

Spring Force

Friction is a force that goes against the motion of an object.

Examples:
- Using the brakes to stop a car
- Roller skating
- Rolling a ball

Without friction, these objects would go on and on forever. Friction slows these objects down until they eventually stop.

Friction

Multiple Choice

____________ is a pulling force that stretches something.

• Tension force

• Spring force

• Friction

Multiple Choice

Contact forces ___________

• act between objects that are touching.

• are not real.

• are between forces that do not touch.

Multiple Choice

__________ occurs in an object that has been stretched or squeezed.

• Tension force

• Spring force

• Friction

Multiple Choice

Which of the following is NOT a contact force?

• gravity

• spring force

• tension force

Multiple Choice

Friction is a force that __________

• stretches something.

• bounces back after being stretched.

• goes against the motion of an object.

What are noncontact forces?

Forces that act at a distance. These forces can act on an object without touching it.

Noncontact Forces

1. Gravity

2. Electricity

3. Magnetism

Three types of noncontact forces are:

Gravity is a force that acts between any two objects that pulls them toward one another.

Examples of gravity:
-The gases in the sun are held together with gravity.
-Water resting in the bottom of a glass instead of hovering at the top.
- The moon revolving around the Earth
- Pouring your milk into your cereal

Gravity

Electric forces act between objects that are electrically charged. Oppositely charge objects are attracted to each other and will move toward one another.
Objects will the same charge repel each other and tend to move away from one another.

Examples:
- Rubbing a balloon on your head to make your hair stick up.
- Receiving a shock after rubbing your socked feet across the carpet

- Going down the playground slide and your hair sticking straight up

Electricity

Magnetism is a noncontact force that can exert a pull on magnetic objects, such as objects with iron.


A magnet does not have to touch the object to attract it. The magnetic field surrounding the magnet either attracts or repels objects.

Magnetism

Multiple Choice

What is one example of a force that pushes or pulls an object without touching.

• magnetism

• contact forces

• friction

Multiple Choice

Gravity is an example of a force that pushes or pulls an object without touching it.

• True

• False

Multiple Choice

What is a pulling force between two objects, such as you and Earth?

What holds you to Earth and doesn't allow you to float above the Earth?

• magnetism

• gravity

• distance

• speed