Double Kinetic Energy

A car is traveling at 15 m/s

1) How fast would the car need to go to double its kinetic energy?

Kinetic Energy(KE) = 1/2 m V2
The first part (1/2 m) doesn’t change, you need a new value for V such that

V(new)2 = 2 x V(old)2
V(new) = (2 x 152)  1/2
V(new) = 4501/2
which is approx. = 21.21 meters per second.

 

2) By what factor does the car’s kinetic energy increase if its speed is doubled to 30 m/s?

When the velocity is doubled, the kinetic energy is four times because in the way we compute kinetic energy is by taking the square of the velocity. 2v2 = 4v2
=4 times

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