Do answer this!
23 Past month, a group of friends went for a jungle safari. They wanted to see the tiger
in the jungle. They were told that tiger comes out at night for his food and in early
morning to drink water. So, they put their tents near the river. In the night, one of the
friends. Aman who could not sleep started walking around the camp. Suddenly, he
saw a tiger at some distance. He was both afraid and excited. He started moving
back to call his friends but suddenly, the tiger jumped towards Aman and he
shouted for help. Hearing his voice, one of his friends came out with a gun and fired
some shots which stopped the tiger in his tracks and fortunately, Aman was saved.
(i) Aman should not have moved out alone in night justify. [1]
(ii) If the man that can fire 50 g bullet with d velocity of 150 m/s. A 60 kg tiger
springs at him with a velocity of 10 ms-l. How many bullets must the man fire
per second in order to stop the tiger in his track? [2]
(iii) Explain the reason for recoiling of gun. [1]
(a) Aman should not move alone in night as tiger comes out in night for his food.
(b)
Mass of a bullet, m = 50 g = 0.05 kg
Velocity of a bullet, v = 150 m/s
So, momentum of each bullet, p = mv = 7.5 Ns
Mass of the tiger, M = 60 kg
Velocity of the tiger, V = 10 m/s
Momentum of the tiger, P = MV = 600 Ns
To stop the tiger, let n bullet be fired such that momentum of the n bullets combined is equal to the momentum of the tiger.
np = P
=> n(7.5) = 600
=> n = 80
So, 80 bullets are to be fired to stop the tiger.
(c)
Bullet fired from the gun
Initially when no bullet is fired the net momentum of the bullet-gun system has zero momentum. When bullet is fired the magnitude of the velocity of the bullet in forward direction is equal to the magnitude of the velocity of gun in the backward direction. The direction of velocity is in opposite direction therefore the net momentum again comes out to be zero and hence the conservation of momentum. This is the reason why recoil of gun is observed.