Question

The kinetic energy of a body of mass $4\,kg$ and momentum $6\,N-s$ will be

• A. 2.5 J
• B. 3.5 J
• C. 4.5 J
• D. 5.5 J

Answer 1

Answer: (C)

4.5 J

Answer 2

Given, $m=4\, kg$
$P=6 N - s$
We know that, kinetic energy of a body,
$K=\frac{P^{2}}{2 m}$
$K=\frac{(6)^{2}}{2 \times 4}$
$K=\frac{36}{2 \times 4}$
$K=45\, J$