Question

2014 32V 40/2
- An 8 gm bullet is fired horizontally into a
9 kg block of wood and sticks in it. The block
which is free to move, has a velocity of 40 cm/
s after impact. The initial velocity of the
bullet is
1)450 m/s 2)450 cm/s 3)220 m/s 4) 220 cm/s​

Answer 1

Answer:

450 m/s

Explanation:

An 8 gm bullet is fired horizontally with Velocity V  m/s

Then momentum

= 8 * V  g m/s

= 8V/1000  kg m/s

Momentum after collision

Weight = 9 Kg + 8 g  = 9.008 kg  ( billet sticks into block of wood)

9.008 * 40  kg cm/s

= 9.008 * 40 /100  kg m/s

= 360.32/100  kg m/s

8V/1000 = 360.32/100

=> V = 3603.2/8

=> V = 450.4 m/s

=> V ≈ 450 m/s