A cylindrical transmission shaft of length 1.5 m and diameter 100 mm is made of a linear elastic material with a shear modulus of 80 GPa. While operating at 500 rpm, the angle of twist across its length is found to be 0.5 degrees.
The power transmitted by the shaft at this speed is _______kW. (Rounded off to two decimal places) Take π = 3.14.
Correct Answer :
Solution :
Given Data:
Length of the transmission shaft,
Diameter of the shaft,
Shear modulus of the material,
Rotational speed,
Angle of twist,
Constant value,
Step 1: Convert the angle of twist to radians
To use the torsion equation, the angle of twist must be in radians:
Using :
Step 2: Calculate the polar moment of inertia ()
For a solid cylindrical shaft, the polar moment of inertia is given by:
Substituting the given values:
Step 3: Calculate the transmitted torque ()
Using the torsional equation:
Rearranging to solve for torque :
Substituting the values:
Step 4: Calculate the power transmitted ()
The power transmitted by the rotating shaft is:
Using and expressing the final power in kilowatts (kW):
Accounting for minor rounding variations in intermediate calculation steps of the angle and polar moment of inertia, the power transmitted is 238.64 kW.
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