Electrical power companies sell electrical energy by the kilowatt-hour, where 1 kWh = 3.6x106 J.
Suppose that it costs $0.15 per kWh to run your
electric water heater. How much does it cost to heat
75 kg of water from 15°C to 43°C to fill a bathtub?

Arocket starts from rest and moves upward from the surface of the earth. for the first 10.0 s of its motion, the vertical acceleration of the rocket is given by ay = 12.80 m/s32t, where the +y-direction is upward. (a) what is the height of the rocket above the surface of the earth at t = 10.0 s? b) what is the speed of the rocket when it is 325 m above the surface of the earth?