Help me with ranking this modern physics problem?

[ailwyn]

Spaceships with the rest lengths Lo (shown below) zoom past an intergalactic speed trap. The officer on duty records the speed of each ship, v. (No ship is going in excess of the stated speed limit of c, so she doesn't have to pull anyone over for a ticket.)

Rank these from shortest to longest based on the masses of the spaceships as measured by the intergalactic police office. Clearly indicate any ties.

http://oi49.tinypic.com/2v2wrcg.jpg

Thank-you

[drystan]

I don't think you meant to ask what you asked "Rank these from shortest to longest based on the masses ...." There is no information linking mass to length; so this cannot be done. But why would the police do that when they have the relative length L(v) = L(v/c) Lo that they can more easily measure as the ships go whizzing by? L(v/c) d= sqrt(1 - (v/c)^2)

Clearly L(v) ---> 0 as v ---> c; so that's how to rank these speeders at the trap; not their masses or even their relativistic inertias.

As you are studying the STOR, you should be able to define the relativistic inertia M and the rest mass m, and show how they are related and how they react, if at all, to the speed of the frame having that mass m.

[kienan]

D- 66.14
E- 79.37
C- 80
A- 96
B- 99.22

just use the formula L=Lo*sqrt(1-v^2/c^2)
i put it in excel and did them all at once