A body is tied at an end of a string of length ’l’ and rotated in a vertical circle. The string is just taut when the body is at the highest point.Velocity of the body when the string is in the horizontal position is

velocity of body executing vertical circular motion is  Vθ=v12-2gr1-cosθ here θ is angle made by the string with rest position of body; θ=900 v1=velocity at lowest point; r= radius of the circle; g= acceleration due to gravity for horizontal position , with body having critical velocity =5gr at lowest point Vθ=90=5gr-2gr Vθ=90=3gr