We know that the earth rotates. If you're in a helicopter and you bring it off on the ground and hover, why doesn't it come down to a different place taking into consideration the movement of the earth?

What is the most useful equation for electric power?

Where is the potential energy throughout the loading, cocking, and releasing of the trebuchet?

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.