A hoop and disc have the same mass and radius. Their rotational kinetic energies are related by the equation
Correct answer: A. K.E of hoop= K.E of disc
- A. K.E of hoop= K.E of disc
- B. K.E of hoop= 2 K.E of disc
- C. K.E of hoop= 0.5 K.E of disc
- D. K.E of hoop= 0.4 K.E of disc
Explanation
The rotational kinetic energy (K_rot) depends on both the mass and the distribution of mass around the axis of rotation, but for objects with the same mass and radius, the form of the object (hoop or disc) does not affect the rotational kinetic energy. Therefore, the rotational kinetic energies of the hoop and disc are equal.
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About Kinetic Energy
Kinetic energy is the energy of motion, given for a nonrelativistic object by K = ½mv², so it depends on mass and the square of speed. Questions connect kinetic energy with work through the work energy theorem, calculate changes in kinetic energy, and distinguish it from momentum and potential energy.
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