An experimenter is inside a uniformly accelerated train. Train is moving horizontally with constant acceleration `a_(0)`. He places a wooden plank AB in horizontal position with end A pointing towards the engine of the train. A block is released at end A of the plank and it reaches end B in time `t_(1)`. The same plank is placed at an inclination of `45^(@)` to the horizontal. When the block is released at A it now climbs to B in time`t_(2)`. It was found that `(t_(2))/(t_(1))= 2^((5)/(4))`. What is the coefficient of friction between the block and the plank?

Answer

`mu = ((3a_(0) - 4g)/(4a_(0) + 3g))`