Peter went swimming at a lake with his friends. they arrived early in the morning. peter walked on the sand around the lake with his bare feet. the sand is cool. at noon, when peter walked around the lake with his bare feet, the sand is very hot. what has made the sand hot at noon?

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)