Work Energy And Power Ques 59
59. A body of mass $3$ $ kg$ is under a constant force which causes a displacement $s$ in metres in it, given by the relation $s=\frac{1}{3} t^{2}$, where $t$ is in seconds. Work done by the force in $2$ seconds is
[2006]
(a) $\frac{3}{8} $ $J$
(b) $\frac{8}{3} $ $J$
(c) $\frac{19}{5} $ $J$
(d) $\frac{5}{19} $ $J$
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Answer:
Correct Answer: 59.(b)
Solution:
- (b) Acceleration $=\frac{d^{2} s}{d t^{2}}=\frac{2}{3}$ $ m / s^{2}$
Force acting on the body
$=3 \times \frac{2}{3}=2$ newton
Displacement in $2$ secs $=\frac{1}{3} \times 2 \times 2=\frac{4}{3} $ $m$
Work done $=2 \times \frac{4}{3}=\frac{8}{3} $ $J$
BETA
