Question

A bullet of mass 10g, moving with A velocity of 20m/s.just comes in rest after piercing A target 10cm thick. What is the average resistance offered by target.

Answer 1

mass of bullet, m = 10 g

initial velocity of bullet , u = 20 m/s

a/c to question, bullet comes to rest after. piercing a target 10cm thick.

so, final velocity of bullet, v = 0 m/s

distance travelled by bullet, s = 10cm

use formula, v² = u² + 2as

0 = (20)² + 2 × a × (10/100) [ 10cm = 10/100 m ]

or, -400 = 2 × a × 0.1

or, a = - 2000 m/s²

hence, retardation of bullet is 2000 m/s²

now, average resistance offered by target = retardation of bullet × mass of bullet

= 2000 × 10/1000 [ 10g = 10/1000 kg

= 20N