Work Power and Energy 1 Question 8
9. A body is moved along a straight line by a machine delivering constant power. The distance moved by the body in time $t$ is proportional to
$(1984,2 M)$
(a) $t^{1 / 2}$
(b) $t^{3 / 4}$
(c) $t^{3 / 2}$
(d) $t^{2}$
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Answer:
Correct Answer: 9. (c)
Solution:
- $P=$ constant
$\therefore$ Work done in time $t$.
$$ W=P t $$
From work-energy theorem, net work done is change in kinetic energy. Therefore,
$$ \frac{1}{2} m v^{2}=P t \text { or } v \propto t^{1 / 2} $$
Integrating, we get $\quad s \propto t^{3 / 2}$
