If the speed of a car is doubled, its kinetic energy becomes
Correct answer: B. four times
- A. double
- B. four times
- C. half
- D. unchanged
Explanation
Kinetic energy depends on the square of the speed, so a factor of two in speed gives a factor of four in energy, and the braking distance rises in the same proportion since the brakes must dissipate all of it. This is the physics behind speed limits. The momentum, meanwhile, only doubles.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
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
The kinetic energy of a body of mass m moving with speed v is
A body of mass 5 kg moves at 4 m s-1. Its kinetic energy is
The kinetic energy of a body is doubled when its
A body of mass 1 kg has kinetic energy 50 J. Its speed is
If P is the momentum of an object and m is its mass, then its kinetic energy is:
A 0.5 kg ball moving at 6 m/s has kinetic energy