A helium atom traveling horizontally collides elastically and head-on with a massive
PHYSICS · Single correct · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A helium atom traveling horizontally collides elastically and head-on with a massive, fixed laboratory wall. Which statement most accurately explains why such atom–wall collisions produce the pressure measured on the wall?
(a) The atom transfers its kinetic energy to the wall surface during the collision; this energy transfer exerts a force that is felt as pressure.
(b) Because the atom reverses its velocity, the change in momentum imparted to the wall is equal to the atom’s initial perpendicular momentum.
(c) The atom reverses its momentum perpendicular to the wall, imparting an impulse equal to twice its initial perpendicular momentum magnitude.
(d) During the collision the atom loses a small amount of speed to internal vibrations in the wall; this loss of speed corresponds to a net force that produces the observed pressure.