Question

A train is moving with the speed of light(c=3*10^8m/s) around the Earth. How much time will it take to complete one round trip along the equator on the surface of the Earth if it's radius is 6400km

Answer 1

t = 0.13 [s]

Step-by-step explanation:

We know that the speed of light is equal to c = 3 * 10^8m/ s, equivalent to 300000000 [m / s] and the radius of the Earth equal to 6400 [km] or 6400000 [m].

The speed definition is given as:

`c = (x)/(t) \\where:\\c = velocity or speed light [m/s]\\t = time [s]\\x = distance [m]`

But we need to know the value of x.

We know that the Earth's equator resembles a circumference, and we need to know the length of the circumference that will be the value of x.

`x =2*\pi *r\\where:\\r = Earth radius [m]\\replacing:\\x = 2*\pi *6400000 = 40212385.97[m]`

Then we can find the time.

`t=(40212385.97)/(300000000) \\t=0.13[s]`