The second law of thermodynamics states that group of answer choices a) energy can be destroyed during nuclear reactions such as those that occur inside the sun. b) none of these is true. c) energy tends to flow from concentrated to less concentrated forms. d) energy can be transformed into matter, and because of this, something is obtained for nothing. e) if energy is gained by one region of the universe, another place in the universe also must gain energy in order to maintain the balance of nature.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.