Question: Will 4.3 ft-lb of torque lift 50 lbs, 10 feet in 30 seconds?

Answer:

Base on 100RPM, No. Torque required to lift 50 lbs at 10 ft/sec is 47.8 ft-lb. That's beyond the rated torque of this motor. The assumption is you are using a motor to drive a drum that has a thin cable that wraps around it like a winch. I just derived this formula for your answer. You may play with it by changing your parameters to see if this motor or someone else's motor would work for you. (Pi/30) * (T/L) * RPM = S where T = Torque (ft-lbs), L = Lift (lbs), RPM = Rotational Speed (rev per minute), and S = Linear Speed of the lift (ft per second). Just in case you decide to play with the diameter of your drum. T = (DIA/2) * L where DIA is the diameter of your drum (ft). Notice when the diameter of the drum decreases, your torque increases but your speed will be reduced. I hope this helps.