Question

A motor rotates a horizontal cylinder, radius 0.50 m, about its axis of symmetry with constant power
at 3.7 kW. A body attached to a rope around the cylinder thereby rises upwards at a uniform speed.

Calculate the body mass if the cylinder speed is 30 rpm. (Answer 240 kg)

Answer 1

Solution) R = 0.50 m

P = 3.7 KW = 3.7×1000 W = 3700 W

w = 30 rpm = (30× (2(pi)))/(60) rad/s

w = 3.14 rad/s

m = ?

P = Tw

Here T is Torque

P = Tw

3700 = (T)(3.14)

T = (3700/3.14)

T = 1178.3 Nm

T = RF

Here F = mg

T = Rmg

m = (T)/(Rg)

m = (1178.3)/(0.50×9.8)

m = 240.45

m = 240 kg