The efficency of a practical machine is less than 100% why?

Which of the following statements are true of solids? a.the particles do not vibrate. b.the particles are in a fixed location. c.they have strong intermolecular forces between the atoms or molecules. d.the particles have less kinetic energy than those of liquids or gases.

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

Awind turbine is rotating counterclockwise at 0.5 rev/s and slows to a stop in 10 s. its blades are 20 m in length. (a) what is the angular acceleration of the turbine? (b) what is the centripetal acceleration of the tip of the blades at t=0s? (c) what is the magnitude and direction of the total linear acceleration of the tip of the blades at t=0s?