Recent content by mstachowsky

Yes...I may not have been clear. Here is the scenario: I have two surfaces in contact, the block and the table. Let's now assume that I have pinned the block through its center so that it is free to rotate so long as I can overcome friction, but it cannot translate (this just makes life...

I promise this isn't homework, it's actually for my research :-P Here goes: When two bodies are in contact and *translate* with respect to each other, there is no dependence of friction on contact area, and Ff = mu*Fn. Now, assume we have a block of wood on a table with mass m and we apply...

Oh, no. Sorry. I was talking about the prof. I mentioned that I'd explain what the question was asking when I found out.

Oh wow. Here's what he wanted us to think about: consider the fact that collisions don't happen instantly. Can you perform the calculations based on a collision that occurs over some small time period t_o? So...yeah. Turns out we CAN consider the time it takes, and therefore the impulse...

Hm, I'm starting to recognize that this may have been a more challenging question that I'd anticipated before :-P I'll have to think a lot more on this, or just ask the prof tomorrow...

Hm, and here we get to my confusion as well: where *does* that extra momentum "come from"?

Haha my typing speed is directly related to how much coffee I've had and how much I'm trying to avoid studying :-P I agree that some energy will be lost, for sure, to heat and deformation, sound etc. But didn't we just ignore all of those things in the equations I put forward? Somehow I've...

So far so good! Thanks for your help, it's really appreciated. Your reply made me look back at my notes and read "Momentum is a vector but for now let's just consider it in one direction". That's probably why I was ignoring the vector stuff so far and why I thought we hadn't been taught that...

Thanks for the reply. The way the prof asked the question didn't specify whether the collision was elastic or inelastic. I just assumed that there was some elasticity (like your stainless steel example) so the bullet keeps traveling in a possibly different direction. We haven't learned about...

Homework Statement Consider a bar of length L, mass M, and uniform density floating in free space (ie: neglect gravity and assume that it is not contacting anything). The bar is initially stationary. Imagine a bullet of mass m traveling at a speed v hits the bar at one end. What is the...