A person is running at a velocity vv. By which factor would they need to increase their speed in order to double their kinetic energy?

The kinetic energy is given by:
[tex]K=\frac{1}{2}mv^2[/tex]If we want to double it then we have:
[tex]2(\frac{1}{2}mv^2)=\frac{1}{2}m(\sqrt[]{2}v)^2[/tex]Therefore the speed has to increas by a factor of square root of 2