Julie and Ashwin were doing an experiment in the classroom. They each had to move a 15 kg box. Julie was able to move her box, but Ashwin was only able to move his after removing half the items in the box. Which is true regarding the force he applies after removing the items from the box?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

What do you think car designers do if the damage caused by a crash test is too severe?