Question

When the momentum of a body decreases by 10%, its K.E. decreases by

• A. 20%
• B. 40%
• C. 36%
• D. None of these

Answer 1

The correct option is D None of these

$\frac{P^2}{2M}=K.E{P}^1=0.9PK.E^1=\frac{{P^1}^2}{2M}={\left(0.9\right)}^2\frac{P^2}{2M}=0.81K.E$

ts $K.E$ s decreased by $19\%$

So the ball has both the $K.E$ and $P.E$