A small block can move in a straight horizontal line along AB. Flash lights from one side project its shadow on a vertical wall which has a horizontal cross-section as a circle. Find radial acceleration as a function of time.
(A) \(\frac{vR^2}{(3R^2t-Rvt^2)}\)
(B) \(\frac{vR}{(2Rt-vt^2)}\)
(C) \(\frac{R.t^{-/3}}{(2R^3t-vR^2t^2)^{2/3}}\)
(D) \(\frac{3}{\frac{2}{\Big(t-\frac{R}{v}\Big)}}vRt\)
