question_answer

A girl is swinging in the sitting position. How will the period of the swing change if she stands up?      

Answer:

                The girl and the swing together constitute a pendulum of time period, \[T=2\pi \sqrt{\frac{l}{g}}\] As the girl stands up, her \[\text{C}.\text{G}.\]is raised. The distance between the point of suspension and the \[\text{C}.\text{G}.\]decreases i.e., length \[l\] decreases. Hence the time period T decreases.