If a solar panel phone charger has a total energy input of 6.25w, and an efficiency of 40% (2.5w), is only 2.5j of energy going to the phone a second?

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n

Anonzero net force acts on a particle and does work. which one of the following statements is true? the kinetic energy of the particle changes, but the speed of the particle does not change. the kinetic energy of the particle does not change, but the speed of the particle does change. the kinetic energy of the particle changes, but the velocity of the particle does not change. the kinetic energy and the speed of the particle change, but the velocity of the particle does not change. the kinetic energy, speed, and velocity of the particle change.

Contains chemical energy. a. heat b. light c. natural gas