Let the body mass be $m$
Let the Acceleration be $a$
According to Newton’s second law of motion, we have,
$F=m a($ constant $)$
As, $\mathrm{a}=\frac{d v}{d t}=$ constant
$d v=d t \times$ constant
On integrating we get,
Where, $\alpha$ is a constant
$\mathrm{v} \propto \mathrm{t} \rightarrow 2$
The relation of power is given by:
From equation $1 \& 2$
$P \propto t$
Thus, we can say that power is proportional to time.