Question

A bullet having a mass of 10kg and moving with speed of 1.5 m/s,penetrates o 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 (give answer in step by step,so i can understand) std 9th,Maharashtra board ,science subject.

Answer 1

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