Laws of Motion
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Question : 19
Total: 40
A shell of mass 0.020 k g is fired by a gun of mass 100 k g . If the muzelespeed of the shell is 80 m s − 1 , what is the recoil speed of the gun?
Solution:
Here, mass of the shell, m 1 = 0.02 k g ; mass of the gun, m 2 = 100 k g Initial velocities of both the shell and the gun are zero i.e. u 1 = u 2 = 0 After firing, speed of the shell, v 1 = 80 m s − 1
Letv 2 be the recoil speed of the gun. According to the principle of conservation of momentum,
m 1 v 1 + m 2 v 2 = m 1 u 2 + m 2 u 2
∴ 0.02 × 80 + 100 v 2
= 0.02 × 0 + 100 × 0 or v 2 = −
= − 0.016 m s − 1
Let
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