text: find the angular velocity in radians per second of a power take off shaft rotating at 750 rpm,? and the linear speed of a point on the rim of a 15.0in diameter pulley. well, each rotation consists of π radians and there are 60 seconds in each minute.  radians/second = π radians * 750 rpm / 60 sec/min  you can surely calculate the linear speed of the edge yourself.