A ball falls, rebounds and reaches a lower height. At the two highest points it is stationary. Its gravitational energy store decreases from 12 J to 7.0 J. No energy escapes from the closed system containing the ball, Earth and surroundings. Which conclusion is correct?
Other stores gain 5.0 J5.0\ \mathrm{J}5.0 J; total energy changes by 0 J0\ \mathrm{J}0 J
Other stores gain 5.0 J5.0\ \mathrm{J}5.0 J; total energy falls by 5.0 J5.0\ \mathrm{J}5.0 J
Other stores gain 7.0 J7.0\ \mathrm{J}7.0 J; total energy falls by 5.0 J5.0\ \mathrm{J}5.0 J
Other stores gain 7.0 J7.0\ \mathrm{J}7.0 J; total energy changes by 0 J0\ \mathrm{J}0 J