(asap will rate and ) compare the potential energy of a 5 lb ball at the top of a 5 foot hill and a 5 lb ball at the top of a 10 foot hill
a their potential energies are the same because they have the same mass.
b the ball at the top of the 5 foot hill has the least potential energy.
c the ball at the top of the 5 foot hill has the most potential energy.
d potential energy doesn't depend on a object's relative height.
2: which of the following has the most potential energy (only 3 answer choices)
a: a car at the top of a hilll
b: a car speeding down a hill
c: a person at the top of a hill

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?