A body of mass 5kg at rest is acted upon by two mutually perpendicular forces 6N and 8N simultanecusly. Its kinetic energy after 10s is,

Given,

m = 5kg

u = 0

from the question,

$\mathrm{Net} \mathrm{force}=\sqrt{{{\mathrm{f}}_1}^2+{{\mathrm{f}}_2}^2}=\sqrt{6^2+8^2}=10$

Force = ma

$\mathrm{a}=\frac{\mathrm{F}}{\mathrm{m}}=\frac{10}{5}=2$

Kinetic energy ,

$\mathrm{KE}=\frac{1}{2}{\mathrm{mv}}^2$

$$\begin{gathered} \mathrm{after} 10\sec , \\ \mathrm{v}=\mathrm{at}=2\left(10\right)=20 \end{gathered}$$

$\mathrm{KE}=\frac{1}{2}\times 5\times 20\times 20=1000\mathrm{J}$

Hence the correct answer is 1000J.