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Homework Statement
An electron has a rest mass of 9.11 x 10^-31 kg. The speed of the electron in the cathode ray tube of your computer monitor is 4.00 x 10^7 m/s. However, the speed of the electron is 0.98 c in a particle accelerator used in cancer therapy. How many times heavier is the electron in the particle accelerator than in the computer monitor?
Homework Equations
m = mo/ sqrt(1 - v^2/c^2)
The Attempt at a Solution
mo1 = m sqrt(1 - v^2/c^2)
= (9.11 x 10^-31 kg) sqrt{ 1 - (4.00 x 10^7 m/s)^2/(3.00 x 10^8 m/s)^2}
= (9.11 x 10^-31 kg) sqrt(0.017777777)
= (9.11 x 10-31 kg)(0.13333333)
= 1.21 x 10^-31 kg
mo2 = (9.11 x 10-31 kg) sqrt{1 - (0.98 c)2/c^2}
= (9.11 x 10-31 kg)(0.198997)
= 1.81 x 10^-31 kg
(1.81 x 10^-31 kg)/(1.21 x 10^-31 kg)
= 1.496 times
Therefore the electron is approx. 1.5 times heavier in the particle accelerator than it is in the computer monitor.
Is this correct?
Thanks