Recent content by spacediver

I've been thinking about this more. I understand that G cannot exert a torque at G. But why can't G experience a net torque due to the forces in the muscle (or spring)? After all, the system does rotate about G, so there must be a torque at G. I guess this is another way of asking how angular...

Here's a video in Algodoo I just created showing the hips moving leftwards due to tension between the two sections (gravity is removed).

oh wow, that looks great, thanks!

Ah, right. I see this now. I think I can see one way this could happen in Cwatters' drawing. The muscle force pulling on the upper rod in the 7 o'clock direction is not perpendicular to the section of the rod it's attached to. Therefore, there is a component of force that is transmitted...

So muscle fiber pulls on rod in a rightward direction (green arrows in my drawing). In reaction to this, the rod pulls leftward on muscle (not shown). This reaction force would cause the muscle to accelerate to the left (just as if I pulled on something, i'd pull myself towards it). The fact...

oh, my original diagram was just implying that the muscle fiber was stiff enough to maintain its curved shape without any force to support it. But I think I see your point. With CWatters' redrawing, I take it point H will still move leftward, as angular momentum must be conserved. As for point...

Understood, and I like the torsion spring idea.

Hmm, I don't follow (but I want to). Are you suggesting that another force is required to maintain its curved shape? Or that the rods must exert an equal and opposite force onto the muscle at the two attachment points? If the latter, I left those out as I didn't think them relevant to the...

Ah, my error. If I'm understanding correctly, to depict them as balanced, the forces must be parallel to each other if they are equal in magnitude, and in my illustration they are not parallel. I designed the system like this to simplify a conceptual problem I'm working on. The muscle fiber in...

This isn't a real homework problem (i.e. I made this problem up myself for my own purposes), but I figured this is the correct forum to post. 1. Homework Statement In the following figure we have two rods connected to each other, and the bottom rod is connected to the blue structure (G), and G...

thanks for the reference. I shall read that paper once I make my way through the Feynman chapter.

Ok I'll try to articulate myself better, and I do appreciate your patience here. In the image below, the speaker is depicted as moving rightwards at a uniform velocity (v), relative to a stationary observer. Also assume that the air is stationary. The green line indicates the membrane of the...

I meant the pistons that are causing the membrane to vibrate, not the overall motion of the speaker itself. Absolutely, just like pushing a canoe across the width of a river with a current. You'd need to aim the canoe at an angle to have it reach a point directly opposite you by the time it...

But wouldn't an impulse waveform be generated by a piston that moves vertically across its amplitude in an infinitesimal amount of time? If so, then there has been no lateral movement during the generation of this wavefront.

Thanks for the detailed reply. In my thought experiment, I used an impulse wave, so the wave is generated in an infinitesimal amount of time. I assume that in this case there isn't any aberration. In other words, the aberration of a sound wave occurs because there are a series of wavefronts...