Desirable and Undesirable Effects of Friction

How can you best reduce friction between the bottom or feet of furniture and the floor?

• by smoothing the floor.

• by keeping furniture on their place.

• by applying lubricants like wax on the floor.

• by putting wheels or rollers on the bottom or feet of furniture and the floor.

Which shows that friction is undesirable?

• Pushing furniture

• Lighting a matchstick

• Walking on wet floors

• Using the breaks when approaching a stoplight

Which of the following is an example of increasing friction?

• Polishing the floor

• Squirting oil into the door hinge

• Waxing the underneath of ice skates

• Spreading sand on a wet road

How is brake useful?

• It uses friction to make vehicles move faster.

• It uses friction to slow down a moving vehicle.

• It uses friction to move the vehicle to any direction.

• It uses friction to move the vehicle easily.

Why are oil and lubricants applied to machine parts?

• To make the parts move easily.

• To prevent the parts to move fast

• To protect the parts from wearing down

• To make the parts move slowly.