Recent content by Screen

Homework Statement I'm trying to understand how to determine the sign (+/-) of a given couple. In the sample problem below it shows the 30 lb couple (on the zy-plane) having a negative value for it's force. Is this found by using the RHR? And if so, in which direction do I orient my hand? In...

Oh you are completely right, sorry for such a silly question and thank you for explaining.

Homework Statement This is probably very simple, but I'm teaching myself arc length via Paul's Online Calculus Notes and there's a simplification on the page: I was wondering why the first Δx^2 was simplified to 1? I understand the other Δx^2 came out of the square root.

Oh, is the velocity referring to the velocity of the vibrating string? I think I understand now.

Read the question carefully; they haven't collided yet.

If you care the problem had nothing to do to with momentum (well, you would use momentum to find the final velocity, but that was already given to you - 10 m/s), instead it was just one dimensional motion. If it starts at 10 m/s, and it takes 13.2 seconds to stop, the acceleration would be...

Try writing it mathematically. The problem is asking about the kinetic energy and momentum of each mass, not the combined total.

Try proving each one and post what you get here. What would cause momentum to be lost?

That means you know the initial velocity and you know the final velocity, and the time it took to stop - what can you find from that? Try listing all the variables you know.

Homework Statement I was told that a string on a guitar vibrates at a frequency of 110 Hz. The length of the string is .648 m and the tension is 100 N. I was told to find the mass per unit length, μ, of the string. Although I got the correct answer, I was wondering why my initial attempt was...