Recent content by luigidorf

That's good info. However, I think I didn't explain the setup well enough because the voice coil only moves on one axis, and the magnets are essentially uniform along that axis for both set ups. Hope that makes sense.

Hi there, I'm building a speaker for my intro to EE class. We were given ten small washer magnets, some washers, a nut and a bolt. Enameled wire is also provided. My group prototyped a speaker with the following configuration: Voice coil wrapped around a paper tube which fits around the bolt...

I was indeed referring to forefoot (and some mid foot) strikes. I was careful to refer to runners with "good form." Heel striking is bad form, and even if the runners in that study were "experienced," they likely still heel strike due to growing up wearing shoes. This discussion actually sheds...

You're right! I already acknowledged such things: I should point out that walking isn't the same as running. Also, the running graphs that you found (thank you by the way) are from a runner with poor form: the spike that occurs around 0.1 s on the vertical force graph is representative of a...

You have to remember that his legs are connected to the rest of his body (and to the other leg). We can agree that the runner's torso doesn't change horizontal velocity, so let's look at both legs combined. In the middle of the runner's landing, his legs are bend and the mass of the legs in...

If you moved your legs in a pogo-stick fashion, and didn't move them back relative to to your body, your foot would be moving relative to the ground as it touched down. Your foot would exert a breaking force on the ground, and the ground would exert breaking force on you. You would fall *** over...

I run barefoot quite a bit and my footprints aren't distinguishable from those of a walking barefoot person (except by their spacing), or from someone who wasn't moving at all and just make a foot print. What would this pogo-stick style of running look like? With regular running with no air...

I was thinking of real ice, not frictionless ice. Unless you're talking about counteracting air resistance, there's no need for a horizontal frictional force when running with good form (with walking it's pretty hard to walk without exerting a significant breaking force, which would mean a...

But once you start moving, it's not hard to keep moving. I believe it's harder to walk on ice because we rely on the friction for stability, not propulsion. Consider this question: what happens to all the force when you're walking on ground? Wouldn't you be constantly accelerating? The way I...

When you're going on a treadmill, you're not trying to move with any speed relative to the rest of your surroundings. Speed is measured relative to the treadmill's belt. Suppose you're on one of those moving walkways at an airport, and you're walking or running in the opposite direction. Then...

Well duh; you are correct that there would be absolutely no difference. My dumb roommate just hasn't come to that level of understanding. His current argument is that people (i.e. runners) don't behave like idealized blocks. I tried to explain that the laws of physics use the word "body" because...

I suggested the airport walkway scenario to him, but he still persisted. The fact that motion is relative should be enough justification, but it wasn't enough for my roommate. When we started drawing FBD's I realized the force that a runner exerts on a ground is (ideally) vertical unless the...

Another treadmill thread: am I more correct than a physics professor? I'm a freshman in college; I took AP Physics C: Mechanics last year in high school. Today my roommate and I got in an argument over whether or not it is easier to run on a treadmill than on flat ground. My friend argues that...

Ah there it is. Thanks!

Homework Statement Homework Equations Q = CV The Attempt at a Solution It's already solved for me; I just don't understand it. In figure (b) it looks like there are two separate conductors: one on top, and one on the bottom. The top piece has +Q on the left side and -Q on the...