Assuming the helicopter is on the ground, and modeling each of its four blades as a slende...

Assuming the helicopter is on the ground, and modeling each of its four blades as a slender rod with weight W = 400 lb and length L = 24 ft, determine the constant moment that must be applied by the engine to the mast at O to spin the blades from rest to an angular speed of 289rpm in 90 s.

Figure P7.36