As shown below AB represents an infinite wall tangential to a horizontal semi-circular track. O is a point source of light on the ground at the centre of the circle. A block moves along the circular track with a speed `v` starting from the point where the wall touches the circle. If the velocity and acceleration of shadow along the length of the wall is respectively `V` and a, then :

Options

A. `V=vcos((vt)/(R))`
B. `V=v sec^(2)((vt)/(R))`
C. `a=((v^(2))/(R))sec^(2)((vt)/(R))tan((vt)/(R))`
D. `a=((2v^(2))/(R))sec^(2)((vt)/(R))tan((vt)/(R))`

Answer

b,d