Question

A bullet of mass 50 g is moving with a velocity of 500 m s^-1. It penetrates 10 cm into a still target and comes to rest.
Calculate:
(a) the kinetic energy possessed by the bullet, and
(b) the average retarding force offered by the target.

April 23, 2024

Answer

Mass = 50 g = 0.05 kg

Velocity = 500 m s^-1

Distance (S) = 10 cm = 0.1 m

(a) The kinetic energy possessed by the bullet = $1\over 2$ × mass × (velocity)²

= $1\over 2$ × 0.05 × (500)²

= $1\over 2$ × 0.05 × 250000

= 6250 J

(b) Work = Force × distance

⇒ Force = $work\over distance$

= $6250\over 0.1$

= 62500 N

∴ Average retarding force offered by target = 62500 N

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