Question

What would be the difference between proper length l0 and the length l measured by an observer moving at 30 m/s for a proper length of 5 m (a reasonable proper length for a car)? Use a similar procedure to the one you used in the previous part. Express your answer in meters to three significant figures. Use c=3×108m/s.

Answer 1

Zero

Step-by-step explanation:

Given:

speed of the observer,
`v=30\ m.s^(-1)`

length of the car,
`l_o=5\ m`

speed of light,
`c=3* 10^8\ m.s^(-1)`

Now as we notice that the observer is moving at a general velocity which is very much less than the speed of the light and hence he/she cannot observe the relativistic length of the car, here only classical physics is applicable.

So the observer will observe the length of the car to be the same as its original length during the motion.