Question

A smooth ring of mass m can slide on a fixed horizontal rod. A string tied to the ring passes over a fixed pulley B and carries a block C of mass 2m as shown below. As the ring starts sliding.

• A. The acceleration of the ring is $\frac{2gcos\theta }{1+2co{s}^2\theta }$
• B. The acceleration of the ring is $\frac{2g}{1+2co{s}^2\theta }$
• C. The acceleration of the ring is $\frac{gcos\theta }{1+2co{s}^2\theta }$
• D. The acceleration of the block is $\frac{g}{1+2co{s}^2\theta }$

Answer 1

The correct option is A The acceleration of the ring is $\frac{2gcos\theta }{1+2co{s}^2\theta }$

$Tcos\theta =ma2mg-T=2mAacos\theta =Aa=\frac{2gcos\theta }{1+2co{s}^2\theta }$