Recent content by theintarnets

Can you show me a brief example please?

Homework Statement A wire of negligible resistance is bent into a rectangle as shown in the figure, and a battery and resistor are connected as shown. The right hand side of the circuit extends into a region containing a uniform magnetic field of 38 mT pointing into the page. Find the...

Oh, I think I got it! I think the signs in the formula switch to + for concave surfaces. When I do 1/di = 1/-12.64 + 1/44.8 I get -17.6. But I think my signs are wrong altogether, because it's supposed to be positive...

Homework Statement A man holds a double-sided spherical mirror so that he is looking directly into its convex surface, 44.8 cm from his face. The magnification of the image of his face is +0.22. What will be the image distance when he reverses the mirror (looking into its concave surface)...

Nvm, I found another formula for phase angle = cos(R/Z) I had the wrong variables written into the equation of Z, so I didn't realize I already calculated XL >.<

Homework Statement "When only a resistor is connected across the terminals of an ac generator (111 V) that has a fixed frequency, there is a current of 0.465 A in the resistor. When only an inductor is connected across the terminals of this same generator, there is a current of 0.360 A in...

Opposite charges attract... I forgot how to add vectors... I saw one formula that multiplied by sin or cos. I assume I use sin if it's got a y component, cos if x. I'm sorry, my professor hasn't taught me a thing about this stuff, and I can't afford the textbook...

So what am I supposed to do? Fnet = F1 + F2, but where do the vectors come in? I'm not sure which ones should be negative or positive... How do I tell?

Homework Statement The drawing shows a positive point charge +q1, a second point charge q2 that may be positive or negative, and a spot labeled P, all on the same straight line. The distance d between the two charges is the same as the distance between q1 and the spot P. With q2 present...

Homework Statement Three point charges have equal magnitudes, two being positive and one negative. These charges are fixed to the corners of an equilateral triangle. The magnitude of each of the charges is 2.9 µC. The lengths of the sides of the triangle are .02m Calculate the magnitude...

I'm having trouble understanding the last two lines of a recurrence relation: 2(log2 n) + kn = n + log2 n * n I get the rest of the recurrence relation, but I don't understand how those two became equivalent. Where did k go? Where did + n come from? and what happened to the 2? Here is...

I don't understand why the answer to this summation: n Ʃ 1/2 i = 0 is (n+1)/2 Why isn't it just n/2?

I know that there's no relationship between i and n, which is why I'm so lost. If I was using i, and it started at 4, would I just subtract the sum of 1 to 3?

I forgot how to do summations... I've been googling all day, but I can't find resources good enough for the types of problems I have. If anyone can provide me with some resources, I'd really appreciate it. Homework Statement 10087 Ʃ6n+8 i=4 I'm just going to call that S Homework...

Wow, thank you so much! I understand it a lot better now.