Laws of Motion 2 Question 4
4. The pulleys and strings shown in the figure are smooth and of negligible mass. For the system to remain in equilibrium, the angle $\theta$ should be
(2001, 2M)
(a) $0^{\circ}$
(b) $30^{\circ}$
(c) $45^{\circ}$
(d) $60^{\circ}$
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Answer:
Correct Answer: 4. (c)
Solution:
- Free body diagram of $m$ is
Free body diagram of mass $\sqrt{2} m$ is
$$ 2 T \cos \theta=\sqrt{2} m g $$
Dividing Eq. (ii) by Eq. (i), we get
$$ \cos \theta=\frac{1}{\sqrt{2}} \text { or } \theta=45^{\circ} $$
