Recent content by jamesmo

Have you gotten to the point where you can use the metric? If so start by writing out your metric. Also, if you can make any useful assumptions (such was weak gravity approximation) try that. If you haven't gotten to metrics yet, where are you so that I can offer a starting point?

Alright, the first thing to try to do is to break it down into a couple of simpler problems, then use superposition. Can you first write down the electric field from a single wire at a distance of z' from the center? If you are completely lost, start with writing down the magnetic fields at...

Alright, the first thing to try to do is to break it down into a couple of simpler problems, then use superposition. Can you first write down the electric field from a single wire at a distance of z' from the center?

You are almost there, but the inequality for the necessary condition is backwards. Does the concept make sense now?

There isn't a singular value, one is the necessary condition the other is the sufficient.

Think about it if A were say, 5 what would that imply for what x is? (-3 or 7) Is the original inequality true? (it isn't) Once you have done that thought experiment, would the inequality be right for 3.5? or 2? I have found messing with inequalities can be tricky, especially when trying to...

If you want to get in the weeds with the calculations, the Feynman Lectures belong on any aspiring physicist's shelf. It may not make to much sense your freshman year, but the pages will be pretty worn by your senior year. I also enjoy the "Demystified" series. They have a lot of example...

A great and entertaining book is Leonard Susskind's "The Black Hole War: my Battle with Steven Hawking to make the world safe for Quantum Mechanics."

Awesome! Have a good one.

Also, write out how to get your C's.

OK, let's kick this off. Can you first get the frequency of the doppler shifted sound wave? I think your equation above (though you haven't defined what each variable represents) should tell you that.

Now think about the other inequality. At x= -2 => |-2-2| = 4 and at x = 5 => |5 - 2| = 3 The necessary condition is the one that has to be met, though there may be other conditions required to make it true. I will let you work out sufficient.

What is the vertical speed there? and the force?

Well, the first step is to solve the equality x2-3x-10 = 0. You will get two solutions. Then you will have to think about what makes the inequality true. The necessary condition is the one that is requried to make the statement true: "For hot dogs to taste good, they must have mustard". The...

First, take the angle piece out of it and shoot the ball straight up. What is the force acting on the ball and how fast is it going at apogee?