Q. In a period of 6.00 s, 6.00 × 1023 oxygen molecules strike a wall with an area of 2.00 cm2. If the molecules move with a speed of 400.0 m/s and strike the wall head-on in elastic collisions, what is the pressure exerted on the wall? (The mass of one O2 molecule is 5.344° × 10-26 kg.)
Q. A playground merry go round of a diameter 6.00 m and mass 240 kg is rotating at 12.0 rev/min about a frctionless vertical axle. Facing the axle, a 30.0 kg child hops on to the merry go round and manages to sit down on its ledge. What is the new angular speed of the merry go round in rad/s?