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# rotational motion

a uniform helicopter rotor blade is 7.8m long , has a mass of 110kg, and is attached to the rotor axle by a single bolt . A) what is the magnitude of the force on the bolt from the axle when the rotor is turning at 320 rev / min . ( hint : for this calculation the blade can be considered to be a point at its com . why ? please answer this as well ). B) calculate the torque that must be applied to the rotor to bring it to full speed from rest in 6.7 s . ignore air resistance . ( the blade cannot be considered to a point mass for this calculation . why not ? assume the mass distribution of a thin uniform rod . ) (C) how much work does the torque do on the blade in order for the blade to reach a speed of 320 rev / min . ?? any help is appreciated .

Note by Bhavya Joshi
4 years, 10 months ago

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320rev/min means 640 rad/min means 10.67rad/sec so omega or angular velocity w= 10.67pie rad/sec the calculate rotational k.e by formula Iwsquare then calcalate angular acceleration by

- 4 years, 1 month ago

rotational inertia of a point mass concentrated at center of mass is I=mrr = 110kg7.87.83

- 4 years, 1 month ago

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