Question

A bullet of mass 25g strikes a wooden target with a velocity of
$100 \: ms { }^{ - 1}$
and emerges with a velocity of
$20ms {}^{ - 1}$
Find the loss in energy during the process of penetration.

Answer 1

Hi there ,

Initial K.E = 1/2 mv^2

= 1/2 × 25/1000 ×100×100

= 125 J

Final K.E = 1/2 × 25/1000 × 20 × 20 =5J

Therefore, loss of K.E , during Penetration= (125 -5)

Answer is = 120 J


$<marquee behavior=move bgcolor= Pink > <h1> ☺️☺️ Thanks!✌️✌️ </h1></marquee>$

Answer 2

$\huge\bold{Solution}$

_______________________________

_________________________________

Given:- Mass of bullet (m) = 25g = 25/1000 kg

Initial velocity of bullet (u)= 100m/s

Final velocity of bullet (v) = 20m/s

Loss in energy = ?

________________________________________

Solution:-

Initial Kinetic energy = (1/2)mu²

initial K. E. = (1/2) × (25/1000) × 100 × 100

= 250/2 = 125 Joule

Final kinetic energy = (1/2)mv²

Final K. E. = (1/2) × (25/1000) × 20 × 20

= 5 Joules

Loss in kinetic energy = Initial energy - final energy

=> 125 - 5

= 120 Joules

______________________________________

Hope it helps u out (　＾∇＾)