Question

Give reasons:
a) A car skids on a wet ground.
b) Ball bearings are used between moving parts
c) It is easier to push an empty trolley than a trolley filled with books.

Answer 1

Answer:

a) lubricant

b)to reduce friction

c) easy to push empty trolley because of less weight

Answer 2

(A) due to less friction. Whenever there is ice or water on the road and there is swamp on the land, the friction between the land and the tires of the car is reduced which causes in skidding of the car.

(B) because the round plain surface of the ball bearing is suitable for movement and it reduces friction between the moving parts hence making it easy to move.

(C) if a trolley is filled with books, it definitely will have more weight and will be heavy as compared to the empty trolley and lesser weight of empty trolley makes it easier to push it as compared to the other trolley.