Question

11.
A sheet of mass 20 g is kept floating horizontally in
air by firing bullets, each of mass 5 g, with the same
velocity, at the rate of 10 bullets per second and the
bullets rebound with the same speed in opposite
directions. The velocity of each bullet at the time
of impact is (Take g = 10 m s?)
A. 2 ms
B. 5 m s-
C. 10 ms
D. 100 m s​

Answer 1

The velocity of each bullet at the time  of impact is 2 m/s.

Explanation:

Given data:

• Mass of the sheet, M = 20 g = 0.02 kg.
• Mass of the each bullet, m = 5 g = 0.005 kg.
• The number of bullets fired per sec, n = 10.

Use the law of conservation of momentum because weight of sheet is balanced by rate change of momentum of the bullets.

Rate change of momentum of the bullets = weight of the sheet

n(m2v) = Mg

Here, 2v because after fired, the bullets rebound with the same speed.

Substitute the values, we get

10 x 0.005 x 2v = 0.02 kgx 0.9 m/s^2

v = 1.96 m/s = 2 m/s

Thus the velocity of each bullet at the time  of impact is 2 m/s.

also learn more

A bullet of mass 60 g is fired from gun of mass 10 kg with a velocity of 60 m/s .Calculate the velocity of recoil of the gun . ?

https://brainly.in/question/2260364