Question

A girl of mass 50 kg sits in a swing formed by a rope of 8m length. A person pulls the swing to a side so that the rope makes an angle of 60° with the vertical. What is the gain in potential energy
of the girl?​

Answer 1

Answer:

Mass of a girl, m = 40 kg

Length of rope of the wing is 6 m

A rope makes an angle of 60 degrees with the vertical.

To find,

The gain in potential energy of the girl.

Solution,

When the swing is pulled apart, the vertical height of the swing is h which is equal to h cosθ = 6 × cos(60) = 3 m

It means that the height with which the swing is raised is, 6 m - 3 m = 3 m

So, the raise in potential energy is given by :

E = mgh

\begin{gathered}E=40\ kg\times 9.8\ m/s^2\times 3\ m\\E=1176\ J\end{gathered}

E=40 kg×9.8 m/s

2×3 m

E=1176 J

It is not ur ans but u can solve it by this process only..

(Collected)