force of friction

Q4. Which is not the advantage of friction?

• Friction helps in walking.

• Friction allows us to write on paper.

• Cars and buses move safely on roads due to friction.

• Friction causes wear and tear.

Q7. Interaction between different types of charges is

• electrostatic force

• muscular force

• frictional force

Q8. Tyres of vehicles have grooved designs to

• reduce friction

• increase friction

Q12. Friction can be increased by increasing the ________of the surfaces in contact.

• Smoothness

• Area

• Roughness

• None of the above

Friction always opposes-

• motion

• force

• weight

• none of these

Which of the following help to increase friction:

• oiling of machine parts

• streamlining the ships

• spikes in shoes

• polishing the surface

A car can skid on wet road due to:

• increased friction between the road and the tyres

• streamlined shape of the car

• reduced friction between the road and the tyres

• both (b) and (c)

A toy car that was moving finally stopped on its own. What is the force that caused the car to stop?

• Gravity

• Push

• Pull

• Friction