Final answer:
The problem presents a physics scenario requiring the computation of time for a boat to decelerate from 100 km/h to 45 km/h with a drag force proportional to speed. Without the specific drag coefficient, the calculation cannot be completed. A solution would involve setting up and solving a differential equation for motion under a velocity-dependent force.
Step-by-step explanation:
The question involves determining the time it takes for a 1000 kg boat to decelerate from 100 km/h to 45 km/h when the engine is shut off. The drag force acting on the boat is proportional to its velocity, which implies that we can use formulas from physics dealing with motion under non-constant acceleration to solve the problem. However, the exact coefficient of drag is not provided, which is necessary for the calculations. To proceed, we would need to know either the specific form of the proportional relationship (such as a constant of proportionality) or an additional point of reference that could allow us to infer it.
Without the drag coefficient, we can only describe the approach qualitatively. We would typically set up a differential equation based on Newton's second law where the net force is equal to the mass times acceleration (F=ma), and the only force acting on the boat once the engine is shut off is the drag force, which is a function of speed. By solving the differential equation we would determine the boat's velocity function over time (v(t)) and then find the time at which v(t) is 45 km/h.
As the specific coefficient is missing from the question, an accurate calculation cannot be provided at this time. One would need to re-ask the question with the drag coefficient included to properly solve this problem and find the time for the boat to slow down to 45 km/h.