Abike rider does work to get to the top of a mountain. how could you use the law of conservation of energy to describe his trip down the mountain? a. the rider uses energy to do work going up the mountain. b. this energy is converted to potential energy and then changes into kinetic energy on the way down. c. the bike rider's stored chemical energy allows him to move down the mountain, storing more and more energy as he goes. d. the bike rider gains electrical energy going up, which changes into electromagnetic energy on the way down.

According to social exchange theory, altruistic behaviors benefit the individual who performs them.

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

A26 cm object is 18 cm in front of a plane mirror. a ray of light strikes the object and is reflected off the mirror at a 42-degree angle. what is the angle of reflection? degrees what type of image is formed? what is the size of the image? cm