Math Is Fun Forum

A smooth track is inclined to the horizontal at an angle of sin-1(3/5). A particle of mass m is placed on the track at a point O, and projected directly up the track with speed 28ms-1. Find how far the particle goes up the track, the speed at which it returnsto O, and the time that it takes from the instant of projection until it gets back to O. What would the corresponding answers be if the plane were rough with coefficient of friction 9/20?

thank you very much in advance.