Question

Give reasons why :
a) Gravitational force should be considered as non - contact force.
b) Rollers are attached to suitcases.
c) Tyres should be retreated occasionally.
d) We should be minimise friction.

Answer 1

Dear Student
(a) Non-contact forces can be defined as the forces which can be applied on the object without contact with the object.

Gravitational force is also applied without contact with objects. eg The birds, Clouds, Moon etc. experience the force without any physical contact with the earth.
(b) Rollers are attached to suitcase because to reduce the friction
(c) Tyres should be retreaded occasionally because of to maintain the grip of tyres
(d) We reduced the friction to minimize the work done by the body
Regards