1. ### I Reconciling alpha particle mass

Ugh ... I remember there was a reason ... but forgot what it was. So here's 3 bits of information gathered from dozens of sources, textbooks, official sites: Alpha particles are identical to Helium nuclei. Alpha particle mass = 4.001506 u helium-4 nuclei mass = 4.0026032 u OK, so ... why...
2. ### Calculating rest mass and energy (in an inertial frame)

Homework Statement A particle is accelerated so it has a total energy of 10GeV measured in the accelerator’s rest frame. The particle's momentum is 8GeV/c in the same frame. Calculate... a.) Rest mass of the particle b.) Energy in an inertial frame in which its momentum is 6GeV/c c.) The speed...
3. ### Intuitive Interpretation of Rest Energy

Hi there, I'm trying to get a better intuitive handle on the concept of rest mass and rest energy - the energy term associated with rest mass. Introductory Physics textbooks often give statements along the lines of "mass is a form of energy" or "mass can be converted to energy" to explain...
4. ### Energy/Momentum transfer from neutrinos to black holes

Suppose you have a source of electron antineutrinos, and you arrange your apparatus so that a billion billion billion of them collide directly with a black hole. In principle, you could measure the change in momentum and energy from that occurrence. Suppose you did that the next day. According...
5. ### Is there a difference between rest mass and invariant mass?

1. is there a difference between 'rest mass' and 'invariant mass'? I thought there wasn't... To put it another way (or maybe this next question is a different question): 2. Is there a difference between the rest mass of a positron/electron pair, and the rest massa of a system containing two...