A block of mass `m` height `2h` and width `2b` rests on a flat car which moves horizontally with constant acceleration a as shown in figure. Determine

a. the value of the acceleration at which slipping of the block on the car starts, if the coefficient of friction is `mu`.
b. the value of the acceleration at which block topples about `A`, assuming sufficient friction to prevet slipping and
c. the shortest distance in which it can be stopped from a speed of `20 ms^(-1)` with constant deceleration so that the block is not disturbed. The following data are given `b=0.6 m, h=0.9 mu=0.5` and `g=10ms^(-2)`