A swing 5 metres long swings through a vertical angle of 50 degrees. Through what vertical distance does the seat rise in going from its lowest position to its highest?

Answer 1

At the lowest point, the swing is 5m below the support.
At the half-vertical angle of 50, the swing is 5m*cos(25°) below the support.
So the vertical distance
= 5m*(1-cos(25°)
Your calculator will give you the approximation to the exact answer.