(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A spacecraft with a proper length of 300m takes 0.75E-6s to pass an earth observer. Calculate the speed of the spacecraft as measured by the earth observer.

3. The attempt at a solution

I'm not sure how to get this, when you plug in those numbers you get 4E8m/s, which is faster than the speed of light. This makes me think that one of the given data needs to be adjusted, but length/time changes all include u, which is what im trying to solve, and this leads to 2 unknowns in 1 equation. If anyone can give me a hint I would appreciate it.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Calculate the speed of the spacecraft

**Physics Forums | Science Articles, Homework Help, Discussion**