Chapter 10: Problem 16
A 25 -cm-diameter circular saw blade spins at 3500 rpm. How fast would you have to push a straight hand saw to have the teeth move through the wood at the same rate as the circular saw teeth?
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Chapter 10: Problem 16
A 25 -cm-diameter circular saw blade spins at 3500 rpm. How fast would you have to push a straight hand saw to have the teeth move through the wood at the same rate as the circular saw teeth?
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You're asked to check the specifications for a wind turbine. The turbine produces a peak electric power of 1.50 MW while turning at its normal operating speed of 17.0 rpm. The rotational inertia of its rotating structure- three blades, shaft, gears, and electric generator-is \(2.65 \times 10^{7} \mathrm{kg} \cdot \mathrm{m}^{2} .\) Under peak conditions, the wind exerts a torque of \(896 \mathrm{kN} \cdot \mathrm{m}\) on the turbine blades. Starting from rest, the turbine is supposed to take less than 1 min to spin up to its 17 -rpm operating speed. The generator is supposed to be \(96 \%\) efficient at converting the mechanical energy imparted by the wind into electrical energy. During spin-up, the electric generator isn't producing power, and the only torque is due to the wind. Once the turbine reaches operating speed, the generator connects to the electric grid and produces a torque that cancels the wind's torque, so the turbine turns with constant angular speed. Does the turbine meet its specifications?
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Do all points on a rigid, rotating object have the same angular velocity? Linear speed? Radial acceleration?
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