Question

A pendulum of length 40 cm is pulled up so the string attached to the bob is completely horizontal. When released, what is the angular acceleration of the pendulum?

Answer 1

Given data:

* The length of the pendulum is,

`\begin{gathered} L=40\text{ cm} \\ L=0.4\text{ m} \end{gathered}`

* The angle of the pendulum with the y-axis is,

`\theta=90^(\circ)`

Solution:

The angular acceleration of the pendulum in terms of the length is,

`\alpha=(g)/(L)\sin (\theta)`

Substituting the known values,

`\begin{gathered} \alpha=(10)/(0.4)\sin (90^(\circ)) \\ \alpha=25rads^(-2) \end{gathered}`

Thus, the angular acceleration of the pendulum is 25 radians per second squared.

Hence, the third option is the correct answer.