Question

A shell of mass 0.2 kg of fired by a gun of mass 100 kg. If the muzzle speed of the shell
is 60 ms, what is the recoil speed of the gun?
(a) 0.12 m/s (b) 0.16 m/s (C) 0.3 m/s (d) 0.4 m/s​

Answer 1

Question :-

A shell of mass 0.2 kg of fired by a gun of mass 100 kg. If the muzzle speed of the shell is 60 ms, what is the recoil speed of the gun?

(a) 0.12 m/s

(b) 0.16 m/s

(C) 0.3 m/s

(d) 0.4 m/s

Solution :-

Given :

• m shell =0.2kg
• m gun =100kg

Explanation :-

From momentum conservation

$\small{ \sf{ \frac{m shell }{v shell }+ \frac{m gun }{v gun} =0}}$

(i) as initial momentum was zero Substituting values from given data in equation

$\small{ \sf{⇒0.2×60+100× v_{gun} =0 }} \\ { \small{ \sf{</p><p>⇒v_{ gun} =−0.016m/s}}}</p><p>$

Answer 2

Correct question:-

A shell of mass 0.2kg is fired by a gun of mass 100kg. If the muzzle speed of the shell is 60m/s, what is the recoil speed of the gun?

(a)0.12m/s (b)0.16m/s (c)0.3m/s (d)0.4m/s

Given:-

▪ Mass of the shell = 0.2kg

▪ Mass of the gun = 100kg

▪ Muzzle speed of the shell = 60m/s

To find:-

▪ Recoil speed of the gun

Solution:-

By using Law of Conservation of momentum, we get:-

=> (-MV)+mv = 0

=> V = mv/M

Where:-

•V is recoil speed of the gun

•m is mass of the shell

•v is muzzle speed of the shell

•M is mass of the gun

=> V = 0.2×60/100

=> V = 12/100

=> V = 0.12m/s

Thus, recoil speed of the gun

is 0.12m/s [Option.(a)]