Recent content by Einstein

I've seen some of them before but there's others which I haven't come across, some have really interesting solutions and comes along with decent interview tips on how to approach these types of questions.

QuantRiddle.com is a very good site to practice common technical and mathematical interview questions. It's useful and entertaining at the same time with many math and physics related information which you can see if you sign up.

I'm trying to understand if a really heavy object on earth, say a mountain, would move if I push it with my bare hands. This sounds absurd but according to Newton's Laws, if I push against the mountain it will exert an equal and opposite force. I understand there are other forces like gravity...

Great post guys. I have just created a website myself - www.tubetor.com. It's very early stages but I am also creating some videos myself to teach. I am concentrating on physics, maths and other subjects I am familiar with and have started putting up videos on there. However, the site is...

A normal distribution can be completely defined by two parameters - the mean and the standard deviation. Given a normal distribution however, say X, how can I use just the mean and the standard deviation to give me conditional expected values for X<=0 and for X>0? I am guessing the distribution...

hmmmm...i c wat ur getting at...is it that..?...are u..?..actually I am not!

So if the photon energy is great, everything we look at is ejecting electrons?

Can any1 explain this process and why it supposedly only works on metals.

If I was traveling at half the speed of light from A to B and another person traveling at half the speed of light from B to A (not directly towards each other, side-by-side), would i be traveling at the speed of light relative to the other person. If so, what would i see when i look at this...

Hydrogen and Helium were the main constituents formed soon (thousands of years?) after the big bang. Why did they not burn (as they are flammable), I am sure the universe was hot enough then to ignite it?

What is the greatest Mathematical puzzle that is unsolved? and why?

"simple" vector problem I need help on the second part of this question: The points A and B have position vectors (4i -11j +4k) and (7i +j +7k) respectively. a) Find vector equation of the line passing through the two points in terms of a parameter t. My answer: r = 4i -11j +4k + t(3i...

How do you do this question, I've spent hours figuring it out: Use the substitution x = 3sint to show that 3 [inte]x^2[squ](9-x^2) dx = (81/16)pi 0