Particle collision Definition and 55 Threads

A 1100 kg car traveling north (+j) at 70 km/h collides at an intersection with a 2000 kg car traveling west (-i) at 48 km/h. The two cars stick together. Find the magnitude and direction of the velocity of the wreckage just after the collision I did pythag. thereom and got 84.9, but it wrong??

Homework Statement Two particles, A and B, have the same rest mass, m. Suppose that, in O, A has 3-velocity (V,0,0) and B is at rest. The particles collide elastically at the origin and after the collision A has 3-velocity (a \cos(\theta), a \sin(\theta),0) while B has 3-velocity (b \cos(\phi)...

Ok, when you use positrons to shoot at stationary electrons in a collider with enough energy so that you make a pair of proton and antiproton. The total energy of the pair would be E = T + MC^2, where M is the total invariance mass of the pair, namely 2*938Mev, or I can use E^2 = (pc)^2 +...

At LEP, electrons and positrons, each of energy E= 45.6 GeV (I guess this is total since it's a particle physics course), are collided head-on, and have exactly the right energy to produce Zo particles at rest. e^+ e^- = Z_0 This is simple but I'm having a bit of trouble with collisions...

why does an alpha particle have the smallest distance to an atom if it aprroaches the nucleus head on?