An electric hoist is used to lift a box using a pulley. The diameter of the pulley is 8 in and the box must be raised 1 foot. find the number of degrees through which the drum must rotate to lift the item 1 foot.
12 : 8 Pi = x : 360 do the arithmetic.
so the correct way to do this is pretty simple. you use the equation: s = r * theta where s = arc length (linear) ..... in this case one foot r = radius of the pulley ( r = d/2 = (8in) / 2 = 4 in theta = the angle you rotate through solving for theta yields: theta = s / r = [1ft*(12in/1ft)] / (4 in) theta = 3 radians if you need your answer in degrees, simply multiply by (180/pi) ...... (360 degrees in 2pi radians) theta = (3 radians) * (180degrees / pi radians) theta = 171.9 degrees
