Recent content by Jurij

how long will the magnet accelerate? Do you know formula on the magnetic force?

Do you have any information about motion of magnet as it rolls down an inclined plane? Maybe some links. Or how to count the magnetic force which stop magnet? Thanks in advance

Is there something that you can't understand in the problem or you don't know how to do it?

Yes. you're right. My english isn't very good. But it should be clear now. Could anyone help me?

OK. I don't know if you understand the task. The numbers have to have at least 2 different digit on some position. For example when we have 5 digit: 1, 2, 3, 4, 5, numbers 1234512 and 1234545 or numbers 5555555 and 1551555 are good. When we have 2-digit numbers we have 5^1=16 numbers and 5...

Could anybody help me? Please, give me at least hint.

Hi. It's one more hard task from cominatorics We have 5 digit. How many 7-digit numbers can we create that each two of them have at least 2 different digit? Could you help me? I think that the answer is 5^6 but don't know how to prove it.

Why is it correct answer? Could you explain it? I think it is too small.

I think that the answer is 5^6=15625 but i don't know how to prove it. Could you help me?

I don't know how to solve the task. Could anybody help me?

Hi. I've got problem with this task. We have 5 digit. How many 7-digit numbers can we create that has at least 2 different digit? Jurij

How polarization influence Goos-Hanchen effect? I googled it but I didn't find it.

It's good idea but I want something more interesting. I want to surprise my teacher.

I must construct a car which is propelled solely by wind energy. The car should be able to drive straight into the wind. Have you got any ideas?