rdnmrsox

I think D made a better choice for the rocket ship question (throwing the rocks). I say this because the ship is losing mass, just like the fuel, and you control the thrust rate.

The pushing from the dock is a one time deal, and only gives you an initial velocity whereas the rock throwing is a continual effort until you run out rocks (much like what would happen when the ship runs out of fuel)

basketball1

oh crap i think you're actually right, totally forgot about the sin90=1

basketball1

with the inclined plane, was it that F(tension)=F(perpendicular) and F(parallel)=f(friction)

oceanangel

Oh I thought it it asked for rocket propulsion from the ground, not the entire time haha oh well, I literally answered that question last minute

Pikafu

Yeah I think that's right basketball1.

What was the one with the light shining through the lens on a flat piece of glass? It asked for what process made alternating light and dark "rings" in the glass and I put polarization.

Also, light microwaves and soundwaves: which can be diffracted?

Sci-Fry

Ahh got the rocket propulsion one wrong. I put that for the inclined plane one, basketball1. That way the parallel and perpendicular forces balance and there is no resultant force, hence a constant velocity.

Hopefully I didn't get more than 10 wrong... I answered all the questions, so it comes down to silly mistakes and generally wrong answers...

EDIT: To the above poster, I put interference - it causes an interference pattern that creates bright and dark fringes due to superposition (I think).

I said that all could be diffracted.

oceanangel

Inclined plane was something like parallel=friction normal=perpendicular.. Forgot the exact choice

oceanangel

Flat glass one was interference 100%

basketball1

no onceanangel i think it was still A, rocket propulsion follows newton's third law exactly, it's just with a rocket the action is so great, that the equal and opposite reaction is also huge. Also to Pikafu and the alternating light and dark "rings" was because of interference i believe. and all three can be diffracted.

Pikafu

#$^%@

Well I got those wrong then...sigh. My first guess was that all 3 could be diffracted. Should have gone with it.

oceanangel

All three can diffract. I still agree with you basketball1. I'm just wondering if the rocket propulsion refers to the actual pushing off the ground or the keeping up in the air

basketball1

also which particle has the greatest ratio of charge to mass? Positron...?

basketball1

propel means a force causing movement. i don't think it has to do with keeping in the air. Just deals with the first cause of movement.

Sci-Fry

What did you guys put for the question about a rocket (or something) travelling at 0.9c towards a planet. What would the distance to the planet be as calculated by someone on the rocket.

Answers included "between 0 and D" and "greater than D but smaller than infinity" where D was the distance calculated by someone on earth. I put greater than D smaller than infinity but I think it's wrong.

Also, I think I misread a question. One of them was asking for the greatest charge:mass ratio. For that I put positron, but I think it might have been asking for mass:charge. Can anyone confirm?

oceanangel

Actually for the rocket, maybe D is right cuz it a conservation of momentum. Although a rocket follows third law, it doesn't push the ground. It actually pushes the burned fuel...