A stone tied to a string of length `L` is whirled in a vertical circle with the other end of the string at the centre. At a certain instant of time the stone is at lowest position and has a speed `u` . Find the magnitude of the change in its velocity as it reaches a position, where the string is horizontal.

Options

A. `sqrt(u^(2) - 2gl)`
B. `sqrt(2 gl)`
C. `sqrt(u^(2) - gl)`
D. `sqrt(2u^(2) - gl)`

Answer

D