A futuristic train rushes past you at an incredible, relativistic speed such that it appears to only be 80% as long as you know it to be. At what speed is that train traveling from the point of view of your reference frame

v = 0.6c = 1.8 x 10⁸ m/s

Explanation:

From Einstein's theory of relativity, we know that the length of an object contracts while traveling at a speed relative to speed of light. The contraction is according to following equation:

where,

L = Relative Length

L₀ = Rest Length

According to given:

L = 0.8 L₀

c = speed of light = 3 x 10⁸ m/s

v = relative speed of train = ?

Therefore,

squaring on both sides:

taking square root on both sides:

v = 0.6c = 1.8 x 10⁸ m/s

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered