alleryStart learning →What practical use is made of the large rotational kinetic energy that a heavy spinning disk can hold?
AIt cools the engine of a moving vehicle
BIt cancels the weight of a moving vehicle
CIt measures the speed of a moving vehicle
DIt stores energy on board a moving vehicle
Answer & Solution
Correct answer: D. It stores energy on board a moving vehicle
1. Rotational kinetic energy is one half I omega squared, and a heavy disk spun fast holds a great deal of it.
2. Flywheels use this to store energy on board a vehicle.
3. Braking can feed energy into the flywheel and later take it back out to accelerate again.
4. Nothing about a spinning disk cancels weight, which needs an upward force rather than stored energy.
_Source: OpenStax College Physics (CC BY 4.0), Ch 10 "Rotational Motion and Angular Momentum", section 10.4 Rotational Kinetic Energy: Work and Energy Revisited_
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