FORCE

Force

A push

or pull

one thing exerts on another

What do you know?(Examples, pictures, definitions, experiences)

Normal Force Weight Applied Force

Tension Friction Air resistance

Which of the following would be a unit that measures force?

1. kilograms

2. ounces

3. pounds

4. meters per second

Units of force

• English system

– Pounds (lbs.)

• Metric system

– Newtons (N)

Quarter pounder

0.22 pounds = 1 Newton

What force is acting up on the skydivers?

1. Normal force

2. Weight

3. Tension

4. Air resistance

What force is acting down on the skydivers?

1. Normal force

2. Weight

3. Tension

4. Friction

What are the two forces acting on these skydivers?

Weight (force because of gravity)

Air resistance

What is the name of the upward force that the table is supplying to

the cell phone pictured below?1. Weight

2. Friction

3. Tension

4. Normal

5. Air resistance

What are the two forces acting on this cell phone?

Weight (force because of gravity)

Normal Force

What are the other two forces acting on the truck?

Friction Applied Force

What is the name of the force drawn

in the picture?

1 2 3 4 5 6

17% 17% 17%17%17%17%

1. Air resistance

2. Weight

3. Tension

4. Friction

5. Normal Force

6. Applied Force

When I hit the brakes in a car, the car comes to a stop because _______ acts

between the tires and the road.

1 2 3 4 5 6

17% 17% 17%17%17%17%

1. Air resistance

2. Weight

3. Tension

4. Friction

5. Normal Force

6. Applied Force

Balanced Forces

When forces are equal in size and opposite in direction.

5 N

5 N

Unbalanced Forces

Forces that are not equal in size OR

45 N 15 N

Unbalanced Forces

Forces that are not opposite in direction.

Net Force

The overall force acting on an object.

Who’s winning and by how much?

Net Force

Net force =

12 N

4 N

12 N

20 N

16 N

What is the magnitude of the net force acting on the object?

20 N

10 N

12 N

10 N

What is the direction of the net force acting on the object?

20 N

10 N

12 N

10 N

1. up

2. down

3. left

4. right

Force vectorsWhen adding vectors, you can move them, but you can’t change the size or direction

4 N

3 N

Given the following picture, how would you describe the weight and

normal force?

1 2

50%50%

1. Balanced

2. Unbalanced

Examples in SMART