GATE 2023 AG – Question 51
A chaff cutter has mean cutting radius.25 m, two knives,300 rpm, and feeds30 maize stalks of 12 mm diameter at a time. Dynamic shear strength.05 N/mm². Flywheel-plus-knives mass40 kg and gyration radius.27 m. Find total shaft power in kW, to two decimals.
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Correct answer: 2.70 to 2.85
Explanation
Total shear force is $30(\pi12^2/4)(.05)=169.646$ N. At cutting radius.25 m, instantaneous cutting torque is 42.4115 N·m and angular speed 31.4159 rad/s, giving cutting power1.3324 kW. Flywheel energy is $E=\frac12mk^2\omega^2=1.43899$ kJ. The keyed total is **about 2.77 kW**,obtained by adding that energy numerically as1.43899 kW to cutting power. This requires an unstated one-second acceleration/replenishment time. At steady speed, a flywheel stores energy rather than continuously consuming its full kinetic energy; average power also needs a cutting-duty history. The source’s key is retained with the missing time/duty assumption disclosed.