# Electromagnetic wave problem

1. Jun 3, 2009

### Cakiemmatdo

1. The problem statement, all variables and given/known dataAn 80 kg astronaut has gone outside his space capsule to do some repair work. Unfortunately, he forgot to lock his safety tether in place, and he has drifted 5.0 m away from the capsule. Fortunately, he has a 1000 W portable laser with fresh batteries that will operate it for 1.0 hr. His only chance is to accelerate himself toward the space capsule by firing the laser in the opposite direction. He has a 10-hr supply of oxygen.

2. Relevant equations
Intensity = P/A
F=ma
Electromagnetic wave F =q(E+ V x B)
E=cB

3. The attempt at a solution I have tried to solve it for F but the thing is we don't have q and also there is a piece of equation that is missing and I don't know what it is since I couldn't find anything to relate in the book

Thanks

2. Jun 3, 2009

### rock.freak667

What exactly are you supposed to calculate or find?

3. Jun 3, 2009

### Cakiemmatdo

Oh, it's asking when the astronaut will reach the capsule

4. Jun 4, 2009

### Redbelly98

Staff Emeritus
Looks like you'll need the momentum of the laser beam.