Phet Energy Skatepark

Friction is a force that acts in an ___________ direction of movement.

• similar
• opposite
• parallel
• west

The amount of friction depends on the weight of the objects pressing together.

• True
• False

What type of friction is not moving?

• static
• sliding
• fluid
• rolling

How can friction be reduced?

• reduce the force acting between the 2 surfaces
• reduce the roughness of the 2 surfaces coming in contact
• use wax, grease or oil
• all of the above are ways of reducing friction

Tags

NGSS.MS-PS2-2

A type of friction that occurs when air pushes against a moving object causing it to decelerate.

• surface area
• air resistance
• velocity
• gravity 

Which of the following is an example of friction that is helpful?

• Brakes used on a bike
• Tires from a car on the road
• Tread on the bottom of your shoes
• All are examples that are helpful

Which of the following is an example of friction that is harmful?

• Pencil marking on paper
• Engine parts wearing out
• sand placed on ice in the winter
• Using an eraser to erase marks

How would the absence of friction affect a marble traveling on a long, straight path?

• The marble’s speed would decrease.
• The marble’s speed would increase.
• The marble would stop immediately. 
• The marble would remain at constant speed.

Tags

NGSS.MS-PS2-2

When two surfaces rub, the irregularities of one surface get caught on those of the other surface?

• True
• False

Rougher surfaces have ...

• greater friction
• less friction
• the same level of friction