Question

An object swings on a thread as a pendulum as shown. The height h = 5 meters. What is the object's speed at point A?

Answer 1

Given,

The height, h=5 m

The potential energy of the object at the point where height is h is equal to its kinetic energy at point A.

Therefore,

`(1)/(2)mv^2=\text{mgh}`

Where m is the mass of the object and g is the acceleration due to gravity.

On rearranging the above equation,

`v=\sqrt[]{2gh}`

On substituting the known values,

`\begin{gathered} v=\sqrt[]{2*9.8*5} \\ =9.9\text{ m/s} \end{gathered}`

Thus the speed of the object at point A is 9.9 m/s