Question

A block slides over a surface and it stops after covering a distance of P metres from the starting point. The same block is now slid over the same surface, but the surface is now lubricated and it stops at a distance of Q metres from the starting point.

Choose the correct option among the following.

• A.
  P > Q as lubrication reduces the friction between the surfaces.
• B.
  P < Q as lubrication increases the friction between the surfaces.
• C.
  P = Q as lubrication does not affect the friction between the surfaces.
• D.
  P < Q as lubrication reduces the friction between the surfaces.

Answer 1

The correct option is D

P < Q as lubrication reduces the friction between the surfaces.
Lubricants are the substances used to reduce the friction between two surfaces.

Hence due to less friction in the second case, the block will slide to a larger distance as compared to unlubricated surface i.e. P < Q.