The factors affecting friction are

• Dependence of friction on the nature of two surfaces

• Dependence of friction on the force with which two surfaces are pressed together

• Don't know

• Friction looks after and affects itself

The factors on which friction depends

• nature of the surfaces

• how hard the objects are pressed together

• both (a) and (b)

• none of these

Which of the following can increase friction?

• Polished surface

• Rough surface

• Smooth surface

• None of these

What determines the amount of friction between two surfaces?

• Nature of the surfaces

• Color of the surfaces

• Temperature of the surfaces

• None of these

A matchstick struck on a matchbox catches fire easily because

• Friction produces heat

• Of chemical reaction

• Matchstick is afraid of us

• Matchstick obeys us because we are their masters