Motion in a Plane - Result Question 19
21. A body constrained to move in $y$-direction, is subjected to a force given by $\vec{F}=(-2 \hat{i}+15 \hat{j}+6 \hat{k}) N$. What is the workdone by this force in moving the body through a distance of $10 m$ along $y$-axis?
(a) $190 J$
(b) $160 J$
(c) $150 J$
(d) $20 J$
[1994]
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Solution:
- (c) Since displacement is along the $y$-direction, hence displacement $\vec{s}=10 \hat{j}$.
Work done $=\vec{F} \cdot \vec{s}$
$=(-2 \hat{i}+15 \hat{j}+6 \hat{k}) \cdot 10 \hat{j}=150 J$
