Work Energy and Power - Result Question 27
30. The kinetic energy acquired by a mass $(m)$ in travelling distance (s) starting from rest under the action of a constant force is directly proportional to
[1996, 1994]
(a) $1 / \sqrt{m}$
(b) $1 / m$
(c) $\sqrt{m}$
(d) $m^{0}$
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Answer:
Correct Answer: 30. (d)
Solution:
- (d) K.E. $=\frac{1}{2} m v^{2}$
Further, $v^{2}=u^{2}+2 a s=0+2 a d=2 a d$
$=2(F / m) d$
Hence, K.E. $=\frac{1}{2} m \times 2(F / m) d=F d$
or, K.E. acquired $=$ Work done
$ =F \times d=\text{ constant } \text{. } $
i.e., it is independent of mass $m$.
