Question

A bullet of mass 50 gm enters a metal sheet with speed of 100 m/s and emerges with speed of 40 m/s. The loss in kinetic energy of bullet is

(1) 105 J 

(2) 42 J 

(3) 210 J 

(4) 140 J

Answer 1

Correct Option is (3) 210 J 

\(|\Delta{k}| =\frac{1}{2}\times\frac{50}{100}\) {100²- 40²}

= \(\frac{50}{2000}\times{140}\times{60}\) 

= 210 J