Question

A boy is swinging on a playground swing. He reaches a maximum height of 0.87 meters relative to the lowest part of this swing. At what height does he reach half of his maximum speed?

Answer 1

As the maximum height is,

`h_(\max )=0.87\text{ m}`

The potential energy of the ball will become zero at the lowest point and kinetic energy will become maximum.

Thus, the height at which the kinetic energy is maximum is,

`h^(\prime)=0_{}`

Thus, the height at which the kinetic energy will become is,

`\begin{gathered} H=(h+h^(\prime))/(2) \\ H=(0.87+0)/(2) \\ H=0.435\text{ m} \end{gathered}`

As the kinetic energy is directly proportional to the velocity.

Thus, the velocity become half of its maximum value at 0.435 m.