One ball rolls along a shelf at a steady rate. A second ball rolls off the shelf and gains speed as it falls in a curved path. Which must have an unbalanced force acting on it?
the ball that is rolling along the shelf
the ball that is falling
both balls
neither bal

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is transformed ⇒ as it changes into other forms of energy.

Calculate the amount of heat produced when 18000 coulombs of charge is transferred in one hour through a potential difference of 50v

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.