Work Energy and Power - Result Question 4
6. Force $F$ on a particle moving in a straight line varies with distance $d$ as shown in the figure. The work done on the particle during its displacement of $12 m$ is
[2011]
(a) $18 J$
(b) $21 J$
(c) $26 J$
(d) $13 J$
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Answer:
Correct Answer: 6. (d)
Solution:
- (d) Work done = area under F-d graph
$ \begin{aligned} & \text{ From } x=0 \text{ to } x=12 m \\ & \frac{1}{2} m v^{2}=100+30-47.5+20 \\ & \therefore v=\sqrt{410}=20.6 m / s \end{aligned} $
$ =[2 \times(7-3)]+[\frac{1}{2} \times 2 \times(12-7). $
