Physics pros

[Eeezee]

Originally posted by: Born2bwire
Nothing gives in this instance because you are measuring the height of the ceiling. The path of the light is perpendicular to the path of motion, so there isn't a Lorentz contraction along the direction of measurement and observation.

You wouldn't be able to observe a Lorentz contraction anyway, since you are sitting in the train car. It is not moving relative to you.

 

[IronWing]

Originally posted by: Eeezee

Originally posted by: Born2bwire
Nothing gives in this instance because you are measuring the height of the ceiling. The path of the light is perpendicular to the path of motion, so there isn't a Lorentz contraction along the direction of measurement and observation.

You wouldn't be able to observe a Lorentz contraction anyway, since you are sitting in the train car. It is not moving relative to you.

Hmm, looks like I choked on setting up the problem. That's what I get for trying to recall a physics problem I read 22 years ago.

 

[911paramedic]

Did your roommate walk to school or use motorized transportation? Anybody that's ever been in a motorized vehicle of some sort should be able to answer this.

Seriously.

When you accelerate from a stop sign which way do you feel your noggin wanting to move? (stay to be more accurate)

 

[DrPizza]

Originally posted by: DT4K

Originally posted by: DrPizza
<-- physics teacher

It tilts backward. Also, I'm guessing that your roommate did see an experiment that's counter-intuitive: a helium balloon on a string (up from the floor) will tilt forward. That's probably what he's remembering.

edit: And, there are dozens of movie clips all over the internet showing both of these. I'll leave the searching up to you.

That was my first thought as well. So yeah, you're roommate is an idiot, but he probably saw the balloon experiment and that's what made him think he's right.
The part he missed is that the reason the helium balloons move forward is that they are less dense than air. So what happens is that when you hit the gas, the air goes backwards(just like a hanging ball), which causes higher pressure in the back and forces the (lighter than air) balloons forward.

Even though you don't have cars, I'm pretty sure he's been in a car. Ask him if he remembers what happened when someone slammed down the gas pedal. Did he find himself moving forward? Didn't think so.