1. A rock, thrown straight up, takes 4.2 seconds to reach its maximum height (g= 9.8 m/s2). a) What was its initial velocity?

b) What was its maximum height?

Aproton is projected toward a fixed nucleus of charge +ze with velocity vo. initially the two particles are very far apart. when the proton is a distance r from the nucleus its velocity has decreased to 1/2vo. how far from the nucleus will the proton be when its velocity has dropped to 1/4vo?

Ben(55 kg) is standing on very slippery ice when junior(25kg) bumps into him. junior was moving at a speed of 8m/s before the collision and ben and junior embrace after the collision. find the speed of ben and junior as they move across the ice after the collision .

The volume of a gas is halved during an adiabatic compression that increases the pressure by a factor of 2.5. what is the specific heat ratio? show the math steps .