Question

Say whether the statements are true or false, 1 The force of friction opposes the motion of an object only when i 2 Rolling friction is less than sliding friction 3. Friction produces heat, and causes damage of machine parts 4 The use of wheels increases friction between surfaces​

Answer 1

Question: The force of friction opposes the motion of an object only when I₂ rolling friction is less than sliding friction.

Answer: True

Reason: Frictional force can only be experienced when the effect of rolling friction is less than that of sliding friction which would ultimately try to oppose the body from sliding.

Question: Friction produces heat, and causes damage of machine parts.

Answer: True

Reason: Indeed, when an object is rubbed on a surface possessing some friction, the object loses some of its parts due to rubbing between the object and the surface.

Question: The use of wheels increases friction between surfaces​.

Answer: False

Reason: Effect of friction is the least on a circular body say a wheel. Very less length of a wheel is in direct horizontal contact with the surface making lesser friction to act on it. That is why, vehicles use wheels in order to overcome maximum frictional force possible and run the vehicle with less fuel.