Your ship has steamed 2014 miles at 22 knots using 680 tons of fuel oil. The distance remaining to your next port is 1766 miles. If you decrease speed to 18 knots, how much fuel will be used to reach that port?
ā¢ Fuel consumption vs. speed ā how fuel used per hour changes when speed changes ā¢ Relationship between distance, speed, and time: ( \text{Time} = \frac{\text{Distance}}{\text{Speed}} \) ā¢ Using the same fuel consumption rate per hour (from the first leg) to estimate fuel for the second leg at a new speed
ā¢ First find how many hours the ship has been steaming so far using time = distance/speed. Then use that time to find the fuel burned per hour. ā¢ Next, calculate how many hours the second part of the trip will take at the new speed, and multiply those hours by the fuel burned per hour. ā¢ Compare the number you get with the choices and think about whether slowing down should increase or decrease the total fuel for the second leg.
ā¢ Be sure you are using fuel per hour, not fuel per mile, when you change speeds. ā¢ Double-check the unit consistency: miles with knots (nautical miles per hour) and hours for time. ā¢ Ask yourself: Does your final fuel amount seem reasonable compared to the 680 tons already burned on the first, longer leg?
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