Question

c) A bullet having a mass of 10 g and
moving with a speed of 1.5 m/s,
penetrates a thick wooden plank of
mass 900 g. The plank was initially
at rest. The bullet gets embedded in
the plank and both move together.
Determine their velocity.
(Ans: 0.15 m/s)​

Answer 1

Answer:

Given :  

mass of bullet= 10g= 0.01kg

velocity of bullet= 1.5m/s

mass of plank= 90g=0.09kg

Total momentum before collision=mass of plank x velocity

=0.01x1.5+0.09x0=0.015 kgm/s

Total momentum after collision=(mass of bullet +mass of plank )x velocity

=0.1 kg x V=0.1 V kgm/s

According to law of conservation of momentum,

Total momentum before collision=Total momentum after collision

0.015kg m/s =0.1 v kg m/s

Thus,velocity acquired by the plank and the bullet = 0.15m/s