Q. A coffee filter of mass 1.5 grams dropped from a height of 2 m reaches the ground with a speed of 0.7 m/s. How much kinetic energy Kair did the air molecules gain from the falling coffee filter? Start from the Energy Principle, and choose as the system the coffee filter, the Earth, and the air.
Q. Two identiocal batteries of emf 11.9 v and internal resistance 0,276 ohm are to be connected to an external resistance R either in series or parallel; if R =0.492 ohm, what is the current in the external resistance in series and in parallel arrangements?