In the scenario presented, the key piece of information is that the graph is a sloped line with a y-intercept of zero when plotting acceleration versus force. According to Newton's second law of motion, \( F = ma \) (force equals mass times acceleration), a straight line through the origin indicates that there is a linear relationship between force and acceleration.
Since the y-intercept is zero, it implies that all motorboats are experiencing the effects of the same mass across the variations in force applied, as acceleration (a) is proportional to force (F).
Given that all five motorboats have the same mass, the correct response would be:
All five motorboats have the same mass, which can be calculated from the graph.
This statement reflects the linear relationship seen in the graph \( (a \propto F) \), allowing one to deduce the mass from the slope of the line, which is equal to 1/mass when force and acceleration are plotted.