A massless string runs around two massless, frictionless pulleys, as shown in the figure below. An object with mass m = 12.2 kg hangs from one pulley....

A massless string runs around two massless, frictionless pulleys, as shown in the figure below. An object with mass m = 12.2 kg hangs from one pulley. A force F is exerted on the free end of the string. What is the magnitude of the force F if the object is lifted at a constant speed?