At 0509, on 26 December, you pass under the...

Question 1 of 29218fork_7353b957245042729a9

At 0509, on 26 December, you pass under the Helena Highway Bridge (mile 661.7 AHP). What has been the average speed of the current since departing Memphis Harbor, McKellar Lake, if you have been making turns for 7.5 mph?

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Question 1 of 29218

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🔍 Key Concepts

• Speed made good (SMG) vs. speed through the water (engine turns) • Using distance ÷ time to find average current speed • Relationship: current = speed over ground − speed through water (downbound)

💭 Think About

• Have you already found the total distance from Memphis Harbor (McKellar Lake) to Helena Highway Bridge from the river mileage? How many miles is that? • From the departure time to 0509, how many hours have actually passed? What is your speed over ground using that time and distance? • Once you know your actual speed over ground, how does the known 7.5 mph through‑the‑water speed combine with the river current when you are going downbound?

✅ Before You Answer

• Be sure you are using river miles (AHP) correctly to get the total distance traveled • Convert the elapsed time from departure to decimal hours before using the speed formula • When you compute current, double‑check the sign and direction: downbound current adds to your speed over ground, upbound current subtracts from it