friction 6

Which of the following shows the presence of friction?

• Cars can continually roll down hills

• Things fall on smooth surfaces

• People stay in place as they move

• Cars stop when the driver steps on the brakes

It is a force that opposes motion between two surfaces sticking or touching together.

• Gravity

• Electrical

• Friction

• Magnetic

It is defined as a push or pull that starts, stops, or changes the direction of a moving object.

• Motion

• Force

• Enery

• Food

Which has the greatest frictional force among these surfaces?

• Polished Floor

• Tiled Floor

• Wet Floor

• Sandy Floor

Friction is a force that opposes motion. It acts in the _____ direction of a moving object.

• Same

• opposite

• upward

• downward

Which of the following statements best describes friction?

• It is a force that occurs when surfaces touch each other.

• It is a force that occurs in smooth surfaces.

• It is a force that occurs between solids and liquids.

• It is a force that occurs only on rough surfaces.

Rougher surfaces have....

• greater friction

• less friction

• the same level of friction

• all these are correct

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 examples are helpful

which of these is an example of undesirable effect on friction?

• keeping our balance

• forest fire

• running on the street

• writing in notebook

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 these are ways of reducing friction