Work Energy and Power - Result Question 11
13. A position dependent force, $F=(7-2 x+3 x^{2})$ $N$ acts on a small body of mass $2 kg$ and displaces it from $x=0$ to $x=5 m$. Work done in joule is
[1992]
(a) 35
(b) 70
(c) 135
(d) 270
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Answer:
Correct Answer: 13. (c)
Solution:
- (c) $W=\int_0^{s} F d x=\int_0^{s}(7-2 x+3 x^{2}) d x$
$ =[7 x-x^{2}+x^{3}]_0^{5}=135 J $
