Question

In: Physics

A helicopter has two blades (see figure), each of which has a mass of 220 kg...

A helicopter has two blades (see figure), each of which has a mass of 220 kg and can be approximated as a thin rod of length 6.7 m. The blades are rotating at an angular speed of 43 rad/s. (a) What is the total moment of inertia of the two blades about the axis of rotation? (a) Determine the rotational kinetic energy of the spinning blades.

Solutions

Expert Solution

Total length of two blades L = 6.7 m + 6.7 m

                                        = 13.4 m

Total Mass of the blades M = 220 + 220 = 440 kg

Angular speed w = 43 rad / s

(a) the total moment of inertia of the two blades about the axis of rotation

               I = ML 2 / 12

                = 6583.86 kg m 2

(a) the rotational kinetic energy of the spinning blades K = ( 1/ 2) I w 2

                                                                                 = 6.086 x 10 6 J


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