Amoving ball with a momentum of 25 kg m / s collides head-on with a wall.
it rebounds from the wall with the same speed but in the opposite direction. the time of the collision is 50 ms.
what is the average force exerted on the wall by the ball during the collision?
a 0.50n b 1.00n c 500n d 1000n
show your working.

Aparticle of mass m is placed in a one-dimensional box of length l. the box is so small that the particle’s motion is relativistic, so that e p2/2m is not valid. (a) derive an expression for the energy levels of the particle using the relativistic energy–momentum relation and the quantization of momentum that derives from connement. (b) if the particle is an electron in a box of length l 1.00 1012 m, nd its lowest possible kinetic energy. by what percent is the nonrelativistic formula for the energy in error?