A hoop and disc have same mass and radius. Their rotational K.E are related by an equation______________?
Correct answer: B. K.E hoop = 2K.E disc
- A. K.E hoop = K.E disc
- B. K.E hoop = 2K.E disc
- C. K.E hoop = 1/2K.E disc
- D. K.E hoop = 4K.E disc
Explanation
Rotational kinetic energy is 1/2 Iω². For the same mass and radius, a hoop has I = MR² while a disc has I = 1/2 MR², so K.E hoop = 2K.E disc. The common mistake is choosing equality because both objects have the same mass and radius, while ignoring their different mass distributions.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
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.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Kinetic Energy questions
If the momentum of an object is increased twice, then what will be the kinetic energy?
A 0.5 kg ball moving at 6 m/s has kinetic energy
If P is the momentum of an object and m is its mass, then its kinetic energy is:
When the speed of a moving body is doubled then___________________?
If velocity is doubled then__________________?
Proton electron neutron and a particles have same momentum. Which of them have highest K.E ?