In reducing engine speed to an efficient...

Question 1 / 270705eccefa3bacbc34ba4d47ccc

Question 1 of 270705eccefa3bacbc34ba4d47ccc

In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.

Question 1 of 27070

In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.

🔍 Key Concepts

• relationship between speed, torque, and power in a rotating shaft • what a reduction gear actually does between an engine and a propeller • why a ship’s propeller cannot efficiently spin at high engine RPMs

💭 Think About

• Think about the basic power formula for rotating machinery: if power stays roughly the same, what happens to torque when speed (RPM) is reduced? • Imagine an engine turning at 900 RPM driving a propeller at 100 RPM through gears. How must the torque at the propeller compare with the torque at the engine to move the ship effectively? • Ask yourself: does a reduction gear mainly ‘waste’ torque, ‘create’ power, or trade one quantity for another while power is transmitted?

✅ Before You Answer

• Recall that power ≈ torque × rotational speed (RPM) for a shaft. • Ask whether a reduction gear is intended to make the propeller easier or harder to turn at low RPM for the same engine power. • Check which option correctly matches: lower RPM at the propeller with what must logically happen to torque if transmitted power stays approximately constant.

Question 1 of 27070

In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.

speed and torque are both reduced

speed is reduced and torque remains unchanged

speed is reduced and torque is increased

speed is sometimes unchanged while torque is increased

Question 1 / 270705eccefa3bacbc34ba4d47ccc

Question 1 of 270705eccefa3bacbc34ba4d47ccc

In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.

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Question 1 of 27070

In reducing engine speed to an efficient propeller speed by the use of reduction gears, __________.