Askier starts from rest at the top of a 40.8 m hill, skis down a 30 degree incline into a valley, and continues up a 32.5 m high hill. the heights of both hills are measured from the valley floor. assume that you can neglect friction and the effect of the ski poles. how fast is the skier moving at he bottom of the valley? what is the skier's speed at the top of the next hill? do the angles of the hills affect your answers?

How much work would be needed to raise the payload from the surface of the moon (i.e., x = r) to an altitude of 5r miles above the surface of the moon (i.e., x = 6r)?

Because air contracts as it cools, the air pressure inside a freezer is typically lower than on the outside. why do ice cubes inside a freezer tend to shrink over time? a. the ice dissolves oxygen from the air, forming a denser crystalline matrix.b. the ice reacts chemically with carbon dioxide in the air, forming gaseous carbon compounds.c. the ice melts, and then the liquid freezes as ice crystals on the bottom of the freezer.d. the ice sublimes, and then the water vapor deposits as ice crystals on the sides of the freezer.

In which of the following would the particles move most rapidly? a. ice at -20 °c b. water at 20 °c c. steam at 110 °c d. boiling water e. ice at 0 °c