An engineer claims to have measured the characteristics of a heat engine that takes in 100 J of thermal energy and produces 20 J of useful work. What is the smallest ratio of temperatures (in Kelvin) of the hot and cold reservoirs?

The sun generates both mechanical and electromagnetic waves. which statement about those wave is true?

The plum pudding model of the atom states that ?

Suppose a wheel with a tire mounted on it is rotating at the constant rate of 2.15 times a second. a tack is stuck in the tire at a distance of 0.373 m from the rotation axis. noting that for every rotation the tack travels one circumference (a) find the tack's tangential speed. (b) what is the tacks radial acceleration?