Final answer:
The statement about throwing a rock into the air is false because as it rises, its kinetic energy decreases and potential energy increases, and vice versa as it falls down. A pebble dropped in water does not create a pulse wave. And the force required to push a box up a ramp is not simply determined by the height and length of the ramp due to additional variables like friction.
Step-by-step explanation:
The statement that throwing a rock into the air would increase the rock's kinetic energy is incorrect. When you throw a rock into the air, its velocity decreases as it rises and consequently its kinetic energy decreases as well due to the work done against gravity. At the peak of its height, the rock has maximum potential energy and zero kinetic energy. As the rock falls back to the ground, its potential energy is converted back into kinetic energy, not the other way around. Therefore, the increase in velocity as it falls does not increase its potential energy but decreases it.
The correct statement is: If a rock is thrown into the air, the increase in its height would decrease its kinetic energy because the energy is converted into potential energy. Then, the increase in its velocity as it falls to the ground would decrease its potential energy as potential energy is converted back into kinetic energy.
For a pebble dropped in water creating a pulse wave, this is also false. The disturbance caused by a pebble in water creates concentric circular waves around the point of impact and is not considered a pulse wave, which typically is a single disturbance moving through a medium.
In the case where a boy pushes a box up a ramp, it's false to think that he must be pushing with exactly 100 N. The force required to move the box up the ramp would depend on a variety of factors, including friction and the efficiency of the ramp.
When considering the statements about an apple falling from a tree, it is true that the apple's potential energy would decrease as it falls and converts into kinetic energy.