Final answer:
The statement is false because the force required to push a box up a ramp is not simply the weight divided by the ramp's length; factors like mechanical advantage and friction significantly influence the necessary applied force.
Step-by-step explanation:
The statement is false. When a boy pushes a box with a weight of 300 N up a ramp that is 1.0 m high and 3.0 m long, the force he must apply is not necessarily exactly 100 N. The force required depends on the mechanical advantage of the ramp, as well as other factors such as friction and the efficiency of the ramp. Simply dividing the weight by the length of the ramp ignores these factors and does not accurately represent the mechanical work done or the actual force applied. The 300 N force is the gravitational force acting on the box, and its component along the ramp determines the necessary applied force to push the box up, which could be less than 300 N due to the mechanical advantage provided by the ramp.