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Question:

how to find moment of inertia?

There's a washload problem which i cannot figure out....A washing machine load in the spin cycle, (much like a centrifuge used to separate fluids), can be modeled as a cylinder which has zero density toward the center, and starting from some inner radius where the clothes (or fluids) begin, increases in density as you move radially outward. If such a washing machine has density of clothes (in SI units) of = 16r + 6, a height of 0.60 m, and only has clothes present from inner radius 0.31 m out to 0.55 m from the center,a) what is the moment of inertia of the wash-load? b) If the metal wash basin in which the clothes rotate has a moment of inertia of 4.00 kg*m2, what is the power of the motor that drives it and the clothes from rest up to 5.00 revolutions per second, in 23.0 seconds?

Answer:

b) If the metal wash basin in which the clothes rotate has a moment of inertia of 4.00 kg*m2, what is the power of the motor that drives it and the clothes from rest up to 5.00 revolutions per second, in 23.0 seconds. This will be work done by torque. work done by torque = torque x radians torque = inertia x alpha (rad/s^2) inertia = 4 kg.m^2 alpha = (5 x (2pi)) / 23 = 1.36591 rad/s^2 T = 4 x 1.36591 = 5.46364 Nm 5 x 2pi = 31.416 rad/s (0 + 31.416)/2 x 23 = 361.283 radians 5.46364 x 361.283 = 1973.92 J work done / time = power 1973.92/23 = 85.82 Watts

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