Questions from College Physics

Q: What is the efficiency of an electric generator that produces 1.

What is the efficiency of an electric generator that produces 1.17 kW·h per kilogram of coal burned? The heat of combustion of coal is 6.71 × 106 J/kg.

Q: A heat pump delivers heat at a rate of 7.81

A heat pump delivers heat at a rate of 7.81 kW for 10.0 h. If its coefficient of performance is 6.85, how much heat is taken from the cold reservoir during that time?

Q: The United States generates about 5.0 × 1016 J of

The United States generates about 5.0 × 1016 J of electric energy a day. This energy is equivalent to work, since it can be converted into work with almost 100% efficiency by an electric motor. (a) I...

Q: The intensity (power per unit area) of the sunlight incident

The intensity (power per unit area) of the sunlight incident on Earth's surface, averaged over a 24 h period, is about 0.20 kW/m2. If a solar power plant is to be built with an output capacity of 1.0...

Q: An engine releases 0.450 kJ of heat for every 0

An engine releases 0.450 kJ of heat for every 0.100 kJ of work it does. What is the efficiency of the engine?

Q: How much heat does a heat pump with a coefficient of performance

How much heat does a heat pump with a coefficient of performance of 3.0 deliver when supplied with 1.00 kJ of electricity?

Q: Emil is tossing an orange of mass 0.30 kg into

Emil is tossing an orange of mass 0.30 kg into the air. (a) Emil throws the orange straight up and then catches it, throwing and catching it at the same point in space. What is the change in the pote...

Q: A house with its own well has a pump in the basement

A house with its own well has a pump in the basement with an output pipe of inner radius 6.3 mm. The pump can maintain a gauge pressure of 410 kPa in the output pipe. A showerhead on the second floor...

Q: An air conditioner whose coefficient of performance is 2.00 removes

An air conditioner whose coefficient of performance is 2.00 removes 1.73 × 108 J of heat from a room per day. How much does it cost to run the air conditioning unit per day if electricity costs $0.10...

Q: A steam engine has a piston with a diameter of 15.

A steam engine has a piston with a diameter of 15.0 cm and a stroke (the displacement of the piston) of 20.0 cm. The average pressure applied to this piston is 1.3 × 105 Pa. What operating frequency i...