Recent content by nejibanana

The first two indices refer to the tensor, (row and column of the matrix) the ",j" then refers to the jth coordinate derivative of the tensor, as is shown in the second notation. From the second notation, I would guess j = 1 -> x and j= 2 -> y. Looks like this is in Einstein summation...

I may have been thinking of permutation as opposed to combinations. Considering the permutations leads to undercounting I believe. For combinations, this page explains the situation a bit. http://en.wikipedia.org/wiki/Combination Basically it gives the formula for if you have n things and...

I would use the Kinematic equations, in particular x = V_o(t) + 1/2 at^2 and V_f = V_o + at. The first equation gives you the distance traveled, once you know the time, which is calculable from the other equation. Using this, the answer comes out as one of the choices you listed. This form of...

As Dick said, both are correct. A trick that will help you in the future is to combine constants. In this case you have 1 + c. Since both are constants you can combine this into a new constant c' = 1+c. Then since the label of the constant is arbitrary, you can call this new constant c, and...

I'm a little rusty with combinatorics, but if you ignore the stipulations, you have 8 seats. Each seat has two possible values, facing forward and facing backwards. So the total amount of combinations for that situation is 2*2*2... = 2^n = 2^8. With the stipulation, you remove 3 of the seats...

I would use the kinematic equations, I think they are what you have listed, the notation throws me off a bit. Using those you should be able to find the velocity of the particle at the point it explodes, and also find out the velocity and angle of the first piece. From there conservation of...

You want to find a transformation matrix to change basis. If we call T our transformation matrix, and we have the operator S_y in the original basis, and S_y' is in the new basis, then S_y' = T* S_y T, where the * denotes the hermitian conjugate. Since S_y' is in the y-basis, it should be...

From what I've read on string theory, extra dimensions would alter our law of gravitation. For our typical 3-D universe, the law of gravitation is an inverse square law. For 4-D it would be an inverse cubic law, 5-D is an inverse quartic and so on. The main problem is that the higher the...

You can start by multiplying each possible combination of pauli matrices. Do that and factor out a 1 or -1, which can be replaced with a Levi-Cevita symbol. Use i = 1, j = 2, k = 3.

You should look up Kinematic Equations in your book or with google.

For change in time I used 7 picoseconds. Velocity changes from 2.13e5 to 0 in 7 ps. And I forget to edit it last night, but it wants the answers in microColoumbs/m^2. So i got 2.13e5/ 7e-12 = a, which resulted in a = 3.04e16. then I found E, so E = (9.109e-31) * (3.04e16) / (1.609e-19) ...

Homework Statement In figure (a) below, an electron is shot directly away from a uniformly charged plastic sheet, at speed vs = 2.13 × 10^5 m/s. The sheet is nonconducting, flat, and very large. Figure (b) below gives the electron's vertical velocity component v versus time t until the return...