Final answer:
The correct answer is False. The statement that a force of 100 N was needed to push a 300 N box up a ramp due to the ramp's dimensions is false because the actual force required depends on the efficiency of the ramp and factors like friction.
Step-by-step explanation:
The statement, "A boy pushed a box with a weight of 300 N up a ramp. He said that, because the ramp was 1.0 m high and 3.0 m long, he must have been pushing with force of exactly 100 N" is false. To understand why we need to consider the work-energy principle and the concept of mechanical advantage provided by a ramp.
When pushing the box up the ramp, the work done against gravity is equal to the gravitational potential energy gained by the box, which is the weight of the box (300 N) times the height of the ramp (1.0 m).
The mechanical advantage of the ramp reduces the force needed to push the box up but the force value is not directly one-third of the weight just because the ramp is three times the length of its height. The actual force depends on the efficiency of the ramp and other factors such as friction.