Question

A body of mass $1 \,kg$ begins to move under the action of a time dependent force $\vec{F}=\left(\hat{i}+3 t^2 \hat{j}\right) N$, where $\hat{i}$ and $\hat{j}$ are the unit vectors along $x$ and $y$ axis The power developed by above force, at the time $t=2 s\,$, will be _________W

Answer 1

The correct answer is 100.
F=ti^+3t2j^​
dtmdv​=ti^+3t2j^​
m=1kg,0∫v​dv=0∫t​tdti^+0∫t​3t2dtj^​
v=2t2​i^+t3j^​
Power =F⋅V=2t3​+3t5
At t=2, power =28​+3×32
=100