A body performs SHM along the straight line segment ABCDE with c as the mid point of segment AE (A and E are the extreme position for the SHM). Its kinetic energies at B and D are each one fourth of its maximum value. The length of segment AE is 2R, if the distance between B and, D is found to be . The value of x is __________.
When the particle crosses point D, its speed is half of the maximum speed. Given that amplitude is 2R