question_answer

A car is moving in a circular horizontal track of radius 10 m with a constant speed of 10 m/s. A bob is suspended from the roof of the car by a light wire of length 1.0 m. The angle made by the wire with the vertical is

A) \[0{}^\circ \]  

B) \[\frac{\pi }{3}\]

C) \[\frac{\pi }{6}\]  

D) \[\frac{\pi }{4}\]

Correct Answer: D

Solution :

[d] Given; \[speed=10\text{ }m/s;\]radius \[r=10\text{ }m\]Angle made by the wire with the vertical \[\tan \,\theta =\frac{{{v}^{2}}}{rg}=\frac{{{10}^{2}}}{10\times 10}=1\Rightarrow \theta ={{45}^{o}}=\frac{\pi }{4}\]