Final answer:
The claim about the 100 percent slope being a 45-degree slope is true, but the boy's assumption regarding the force needed to push the box up the ramp is false because it does not consider factors like friction.
Step-by-step explanation:
The statement that a 100 percent slope is equal to a 45-degree slope is true. A 100 percent slope means there is a rise of 100 feet for every 100 feet of horizontal run, which corresponds to a 45-degree angle. However, when calculating the force necessary to push an object up a ramp, the situation differs.
In the case of the boy pushing a box up a ramp that is 1.0 m high and 3.0 m in length, we cannot simply conclude that the force exerted was exactly 100 N without considering other factors such as friction and the mechanical advantage provided by the ramp. Therefore, the boy's statement that he must have been pushing with a force of exactly 100 N is false.