# Recent content by Kevin Willis

1. ### Length contraction accounted for in relativistic aberration?

I have been coding a speed of light simulator and I am having a bit of trouble with a few aspects of the project. My first question is: Are the length contraction and relativistic aberration formulas BOTH needed in my calculations or does the relativistic aberration formula already account for...
2. ### Too late for a 16 year old to pursue a career in Physics?

Never be afraid to fail, don't listen to the naysayers, work hard, and have some fun along the way. If your goals are realistic, you should be motivated enough that nothing will stop you from trying to reach them.
3. ### Finding average angle in kinetic theory of gases

I do mean angle from the normal. In the OP I wrote "(NOTE: I measured the angle from the plane and should have shown measurement from the z axis down to satisfy the cos(theta)." directly under the diagram. So, cos(theta) here is measuring perpendicular distance. Parallel would be sin(theta). I...
4. ### Finding average angle in kinetic theory of gases

This should be the average of cos(θ).
5. ### Finding average angle in kinetic theory of gases

Homework Statement "Show that particles hitting a plane boundary have travelled a distance 2λ/3 perpendicular to the plane since their last collision, on average." Homework Equations (Root mean path squared) <x> = 2^(.5)λ λ = ( 2^(.5) * n * sigma )^(-1) ANSWER: The Attempt at a...
6. ### Programs Are astrophysics majors outcasts of the physics department?

I will be a Junior this Fall at a large and well-known public university. I am working towards a double major of physics and astronomy. I was told by a professor (at a different university) whom I had befriended that due to my interests in astronomy I should expect a certain attitude from other...

Yeah, the example with dropping the ball sure is. Although it posseses PE until the ball has hit the ground. If the ball lost all it PE at halfway through the fall it would stop in mid air. There would be no potential for it to fall further.

It helps to know that PE is relative to the system you are talking about. For example dropping a marble onto a train floor when the train is moving at 50m/s. Relative to the train, the PE is simple gravitational potential, but the PE of the marble relative to the earth is much larger. If the...
9. ### Galaxy viewed in naked eye

The problem is that most of the worlds population is not able to do that. Light pollution and weather are the major reasons people can't see most of the sky. I live in a city where on our best nights we can see only the major constellations. Deep sky viewing even from my 12 inch DOB is...
10. ### Galaxy viewed in naked eye

A month ago here in Florida, my astronomy club and I were on a trip to possibly the least light polluted place in Florida and we could clearly see Andromeda and a few other faint objects (can't remember what the others were). Newbie astronomer here trying to get some hands on experience before I...
11. ### Hawking radiation , black hole size

Yikes, apparently the use of the word proximity is not sufficient here. I will surely be more careful with my wording on PF. I am spending more time explaining my words in deeper detail than I am learning. Also I must be wrong with many others on the inverse square law being non exponential...
12. ### Hawking radiation , black hole size

1/r^2 is a exponential equation. Hense the exponent. And your "proving me wrong" about black hole absorbsion of objects within a certain proximity actually proves me right. Your example of a black hole consuming the sun shows that your theoretical black hole absorbed something in a certain...
13. ### Hawking radiation , black hole size

Remember that although the black hole gets bigger, it still obeys the law of gravity which means that the gravitational pull weakens exponentially with distance. Eventually after it consumes everything in a certain proximity of itself, the other "close" objects will be bound to a stronger pull...
14. ### Coulomb's Law

Jano L. Thank you very much for your insight. That is very useful information. I am in Physics 1 and in the past physics classes I have had we used s for distance variables in almost all cases I can remember. These were pulled straight from the physics books. So, indeed it is a surprise to me...
15. ### Coulomb's Law

Sure guy. Im not going to argue with you. If you cant see my point, no problem. In my mind, if you are talking about a distance between two points it is usually "s" and not "r" because that is known as radius of a circle. Very simple concept to understand. Coming up with reasons to not...