Recent content by nikolafmf

Thank you. So conservation of momentum would be the right thing. I have also found that inner forces in the system are relevant for the change of the kinetic energy of a system, but not for the change of momentum. And I do have change of inner forces in this system.

Homework Statement Truck is connected to a car with a rope of given length. The truck starts accelerating with a given acceleration and at some moment starts pulling the car. What is their common velocity just after the car starts moving? Homework Equations I know how to calculate the...

Btw, can you, or somebody else, suggest me some popular or semi-popular book (first year undergraduate university textbook also acceptable) which explains those things?

Which wire?

OK, thank you very much.

Thank you very much for your answer. My probe was like this: https://i5.walmartimages.com/asr/6f1c3239-8091-4b66-805e-3e1a19b90aa4_1.f2fd69f129c0bf35095d15c5117730e7.jpeg?odnHeight=450&odnWidth=450&odnBg=FFFFFF Is it very likely that I can physically make contact with both Line and Neutral in...

Hello, I was trying to check with a voltage tester if there was voltage in a light bulb socket (Edison type, no bulb present). Explosion happened (a relatively loud sound) and the safety circuit switch turned off. My question is, how can one explain this with the laws of physics and how can...

Hm, I think that I have solve the problem with pressing the DVD a little more :). Strange, but it was then put inside. So, this is solved, I think. Thank you for the interest.

I am afraid I can't. But do you see what is the problem?

Do you mean if it ever accepted DVDs? Yes, it did. But today, suddenly, 3 parts came out off the central cilinder, so it can't anymore. Here are some photos: https://drive.google.com/file/d/0B-esWgIfGKUtVERZWjVqM2JQQlU/view?usp=sharing...

Hello, My DVD drive won't accept disks, mechanically. I can't put any disc in. The problem is this: out of the central circle came three parts which make the radius of the central circle larger, so disc won't fit in. How can one solve this? I send a picture to explain the problem. The large...

OK, thank you very much.

"I assume that what you mean by this is: take the sum of the 4-momenta of the particles going into an interaction, and take the squared norm of the resulting 4-vector; take the sum of the 4-momenta of the particles coming out of the same interaction, and take the squared norm of that resulting...

Hello, I am studing elementary particle physics and want to ask something, just to check if I have understood properly. So, as I understand, this is true about four-momentum in special relativity: 1. The square of the sum of particles' four momenta is invariant under Lorentz transformations...

I see, it was my mistake. He was determining the relative speed between the ether and the Earth, as far as I can see. So he found that it should be much less than Earth's orbital speed.