Question

A force od 10 kgf is applied on a body of mass 100 g initially at rest for 0.1 s calculate:

a) the momentum acquired by the body

b) the distance travelled by the body in 0.1s. Take g = 10 N kg^-1

Answer 1

Mass of body = 100 g = 0.1 kg

Initial velocity,  u = 0 m/s

Time, Δt = 0.1s

a) Force x change in time = change in momentum

Force, F = 10 kgf = 10 x 10 = 100 N

(∵ 1 kgf = 10 N)

F x  Δt = Δp (change in momentum)

100 x 0.1 = Δp

Δp = 10 KG m/s

b) F = 100 N

Mass = 100g = 0.1 kg

F = ma

100 = 0.1 x a

Acceleration a = 1000 ms^-2

From equation

`S = ut + 1/2 at^2`

`S= 0 xx 0.1 + 1/2 xx 1000 xx 0.1 xx 0.1`

S = 5 m