Cindy exerts a force of 40 newtons and moves a chair 6 meters. her brother andy pushes a different chair for 6 meters while exerting a force of 30 newtons andy does work than cindy. the difference of thier amounts of work is

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.

Photons with the highest energy have the longest period

Which planet do you think would be easiest for humans to colonize some day?