A rifle man, who together with his rifle has a mass of 100 kg, stands on a smooth surface fires 10 shots horizontally. Each bullet has a mass 10 g projected with velocity of 800 m/s. What velocity does rifle man acquire at the end of 10 shots?
A rifle man, who together with his rifle has a mass of 100 kg, stands on a smooth surface fires 10 shots horizontally. Each bullet has a mass 10 g projected with velocity of 800 m/s. What velocity does rifle man acquire at the end of 10 shots?
The correct option is A -0.8 ms-1
Let m1 and m2 be the masses of the bullet and the rifleman and v1 and v2 their respective velocities after the first shot.
initially the rifle man and the bullet are at rest, therefore initial momentum is zero.
As external force is zero, momentum of the system is constant.
i.e initial momentum = final momentum
m1v1+m2v2 = 0
v2 = -m1v1/m2
v2 = - 0.08 m/s
velocity acquired after 10 shots = 10 v2 = 10 x (-0.08) = - 0.8 m/s
i.e. the velocity of rifle man is 0.8 m/s in a direction opposite to that of bullet.
-0.8 ms-1
Let m1 and m2 be the masses of the bullet and the rifleman and v1 and v2 their respective velocities after the first shot.
initially the rifle man and the bullet are at rest, therefore initial momentum is zero.
As external force is zero, momentum of the system is constant.
i.e initial momentum = final momentum
m1v1+m2v2 = 0
v2 = -m1v1/m2
v2 = - 0.08 m/s
velocity acquired after 10 shots = 10 v2 = 10 x (-0.08) = - 0.8 m/s
i.e. the velocity of rifle man is 0.8 m/s in a direction opposite to that of bullet.
