Question

A small ball of mass 100 g is attached to a light and in extensible string of length 50 cm. The string is tied to a support O and the mass m released from point A which is at a horizontal distance of 30 cm from the support. Calculate the speed of the ball at its lowest point of the trajectry

• A. 2.2 m/s
• B. 2.5 m/s
• C. 3.2 m/s
• D. 2.4 m/s

Answer 1

The correct option is C 3.2 m/s

$wall=\Delta k$

$\Rightarrow mg\left(\frac{50}{100}\right)=\frac{1}{2}m{v}^2$

$\Rightarrow v^2=\frac{2\times 10\times 50}{100}$

$\Rightarrow v=\sqrt{10}\approx 3.2m/s$

Hence,

option $C$ is correct answer.