A flywheel is attached to an engine to keep its rotational speed between 100 rad/s and 110 rad/s. If the energy fluctuation in the flywheel between these two speeds is 1.05 kJ then the moment of inertia of the flywheel is _______ kg.m² (round off to 2 decimal places).
Correct Answer :
Correct answer is : 1
ω1 = 110 rad/sec, ω2 = 100 rad/sec, ΔKE = 1.05 kJ = 1050 J
1050 =
Solution :
The correct answer is 1.
Understanding the Concept of Flywheel Energy Fluctuation:
A flywheel is a mechanical device specifically designed to store rotational kinetic energy. The kinetic energy () of a rotating body is given by the formula:
where:
- is the moment of inertia of the flywheel (in kg.m²),
- is the angular velocity (in rad/s).
When the rotational speed fluctuates between a minimum speed () and a maximum speed (), the energy stored in the flywheel fluctuates as well. The maximum fluctuation of energy () is the difference between the kinetic energy at the maximum speed and the kinetic energy at the minimum speed:
Factoring out the common terms, we get:
Step-by-Step Derivation and Calculation:
Given the following data:
- Maximum angular speed,
- Minimum angular speed,
- Energy fluctuation,
Substitute these values into the energy fluctuation formula:
Calculate the squares of the angular speeds:
Find the difference between the squares:
Now, substitute this back into the equation:
Simplify the equation:
Solve for the moment of inertia ():
Thus, the moment of inertia of the flywheel is 1 kg.m².
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