Force Quiz 2

What is the main cause of friction?

• Magnetic pull

• Roughness between surfaces

• Heat

• Electrostatic charge

Rolling friction is __ than sliding friction.

• Greater

• Equal

• Less

• Same

Which of these will reduce friction?

• Making surface rough

• Using sandpaper

• Using oil or grease

• Increasing weight

Grooves in car tyres help to:

• Reduce sound

• Look stylish

• Increase friction

• Reduce weight

Friction is useful in:

• Wasting energy

• Wearing out machines

• Walking without slipping

• Making roads slippery

When friction is not useful, we should:

• Increase it

• Remove it completely

• Reduce it using lubricants

• Add sand to the surface

Which friction acts when two surfaces are at rest?

• Sliding

• Rolling

• Static

• Dynamic

Which friction acts when an object is in motion over another?

• Static

• Sliding

• Resting

• Normal

The force that slows down moving objects is:

• Muscular force

• Friction

• Gravity

• Pressure

The rubbing of surfaces produces:

• Light

• Air

• Water

• Heat