A conveyer
belt is to be selected among the four options available for a manufacturer.The
selection criterion is that the material of the belt offer the required
coefficient of friction so that the mass of 10 kg that is carried by the
conveyer of radius 3m, that travels at 0.5 m/s first begins to slip off
at an angle of 25^{o}. 1) m_{s} = 0.51. 2) m_{s} = 0.23. 3) m_{s} = 0.12. 4) m_{s} = 0.42 

Since the belt moves
with constant speed,a_{t} = 0. 