Laws Of Motion Ques 26
26. Three forces acting on a body are shown in the figure. To have the resultant force only along the $y$ - direction, the magnitude of the minimum additional force needed is:
[2008]
(a) $0.5 N$
(b) $1.5 N$
(c) $\frac{\sqrt{3}}{4} N$
(d) $\sqrt{3} N$
Show Answer
Answer:
Correct Answer: 26.(a)
Solution:
- (a) The components of $1 N$ and $2 N$ forces along $+x$-axis $=1 \cos 60^{\circ}+2 \sin 30^{\circ}$
$=1 \times \frac{1}{2}+2 \times \frac{1}{2}=\frac{1}{2}+1=\frac{3}{2}=1.5 N$
The component of $4 N$ force along $-x$-axis
$=4 \sin 30^{\circ}=4 \times \frac{1}{2}=2 N$.
Therefore, if a force of $0.5 N$ is applied along $+x$ axis, the resultant force along $x$-axis will become zero and the resultant force will be obtained only along $y$-axis.
BETA
