Question

A bullet of mass 20g is fired from a rifle with a velocity of 800 m/s after passing through a mud wall100cm

Answer 1

Answer:

Explanation:

Given A bullet of mass 20 g is fired from a rifle with a velocity of 800 m/s after passing through a mud wall 100 cm t he velocity drops to 100 m / s. What is the average resistance of the wall neglecting friction due to air?

We know that mass m = 20 g, initial velocity u = 800 m/s, final velocity v = 100 m/s

Mass m = 0.02 kg

Now there is a loss in kinetic energy.

Therefore loss in kinetic energy will be

 ½ mu^2 – ½ mv^2

½ m(u^2 – v^2)

½ x 0.02 (800^2 – 100^2)

= ½ x 0.02 x (800 + 100)(800 – 100)

= ½ x 0.02 x 900 x 700

= 6300 J

Now according to work-energy formula we know that

W = F x S ( S = 100 cm = 1 m)

6300 = F x 1

So F = 6300 N