Question

a) Define S.I. unit of force.

b) Mention any two effects of force.

(c) A body of mass 60 kg has a momentum of 300 kg m/s. Calculate its velocity.(d) Why does a carpet beaten with a stick release dust ?

Answer 1

a) SI unit of force is Newton.

A force of 1 Newton is defined as the amount of force necessary to accelerate a mass of 1 kg by 1 ms^-2. It is denoted by N.

1N = 1kg × 1 ms^-2

b)

Two effects of force are

i) Force produces acceleration on a body upon which it acts.

ii) Force changes momentum of a body.

c) Here m = 60 kg

p = 300 kgms^-1

p = mv

=> v = p/m = 300/60

= 5 ms^-1

d) Dust flies off because of inertia of rest of the dust. When the carpet is beaten it comes to movement at once and the dust still remains in rest so it comes out.