Question 74Navigation Problems

The correct answer is A) -5.6%. To calculate the apparent slip, we can use the formula: Apparent Slip = (Theoretical Speed - Actual Speed) / Theoretical Speed x 100 The theoretical speed is calculated using the propeller diameter, pitch, and RPM: Theoretical Speed = Propeller Diameter x Pitch x RPM / 33,000 Theoretical Speed = 21.5 ft x 24.5 ft x 78 RPM / 33,000 = 481.68 miles The actual speed is the observed distance of 458 miles in 23 hours, which is 19.91 miles per hour. Plugging these values into the formula: Apparent Slip = (481.68 miles - 19.91 miles) / 481.68 miles x 100 = -5.6% The other options are incorrect because: B) -12.3% is too high C) +12.3% is the wrong sign, as the slip is negative D) +5.6% is the wrong sign, as the slip is negative.