Question

The momentum of a body having kinetic energy E is halved then the final kinetic energy

• A. 2 E
• B. $\frac{E}{2}$
• C. 4E
• D. $\frac{E}{4}$

Answer 1

The correct option is D $\frac{E}{4}$

Let a body of mass $m$ and momentum $p$

Kinetic energy , $K_1=\frac{p^2}{2m}=E$

Momentum is halved , $i.e,\frac{p}{2}$

Final Kinetic energy , $K_2=\frac{(\frac{p}{2}{)}^2}{2m}=\frac{p^2}{8m}=\frac{E}{4}$