When the speed of your car is doubled, by what factor does its kinetic energy increases?
Correct answer: C. 4
- A. √2
- B. 2
- C. 4
- D. 8
Explanation
K.E = 1/2 mv2 Since mass is constant K.E ∝ v2 v' = 2 v K.E' ∝ (2v)2 K.E' ∝ 4 v2 K.E' / K.E = 4v2 / v2 = 4 K.E' = 4 K.E ==> K.E increases by 4 times.
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Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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