Friction and Gravity Video Lesson

What is friction?

• A force that speeds things up.

• A force that pushes things away.

• A force that opposes motion.

• A force that makes things lighter.

How does using the brakes on a bike slow it down?

Is friction a pushing or pulling force?

• pushing

• pulling

• neither

• both

How do we use friction to benefit us?

Which of the following is an example of friction converting motion into heat?

• Writing with a pen on paper.

• Rubbing your hands together to keep warm.

• Using bicycle brakes to slow down.

• Roller skating on a smooth sidewalk.

Is gravity a pushing or pulling force?

• pushing

• pulling

• neither

• both

What is the primary role of gravity on Earth?

• To make surfaces rough.

• To push objects upwards.

• To keep objects floating in the air.

• To pull things down to the center of the Earth.

Why do astronauts on the Moon fall back down more slowly than on Earth?

• The Moon has a thicker atmosphere.

• The Moon is much larger than Earth.

• The Moon's gravity is not as strong as Earth's.

• Astronauts wear heavy suits that slow them down.

What factors affect the strength of gravity?

What is the sum, or combination, of all forces acting on an object?

• Net force
• Applied force

• Resultant force
• Total force