Question

An electron is doubled from .2c to .4c.By what ratio does it's momentum increease?(b)What happens to the momentum ratio when the electron speed is doubled again from 0.4c to 0.8c.

Answer 1

a) Relativistic momentum:

$$p=\frac{mv}{\sqrt{1-(\frac{v}{c})^2}}$$

The ratio will be

$$\frac{\frac{0.4}{\sqrt{1-0.4^2}}}{\frac{0.2}{\sqrt{1-0.2^2}}}=2.138$$

b) The ratio will be

$$\frac{\frac{0.8}{\sqrt{1-0.8^2}}}{\frac{0.4}{\sqrt{1-0.4^2}}}=3.055$$