**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 V**^{2}

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 15^{2}) ^{1/2}

V(new) = 450^{1/2}

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. 2v^{2} = 4v^{2}

**=4 times**