Question

The bullet of mass 4×10-^2 kg moving with a velocity of 20m/s pierces through a sand bag and comes to rest in 0.25 sec . What is the initial momentum of the body in (Kg-m/s) ​

Answer 1

Answer:

Mass of the bullet is m

b

=50gm=0.05Kg

Initial velocity of bullet u

b

=100m/s

Final velocity is v

b

=0m/s

(1) Initial momentum of bullet p

i

=m

b

u

b

=5Kgm/s

(2) Final momentum of bullet p

f

=m

b

v

b

=0.05×0=0

(3) Retardation occurred by the wooden block is

v

2

−u

2

=2as

−(100)

2

=2a(0.02)

a=−250000m/s

2

(4) Resistive force

F=ma

=0.05×−250000

=12500N