Gyroscopic effect on a ship: Determine bow/stern reaction for given rotation/turn. Given: Rotor spins clockwise when viewed from the stern. The ship turns right (starboard) while moving forward. State the resulting pitching effect due to the gyroscopic couple.
Mechanical Engineering
Theory of machines
Difficulty: Medium
Choose an option
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ARaise the bow and lower the stern
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BRaise the stern and lower the bow
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CNo pitching; only rolling occurs
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DNo effect (gyroscopic couple is zero)
Answer
Correct Answer: Raise the stern and lower the bow
Explanation
Concept/ApproachAngular momentum (H) is along the shaft. Clockwise rotation seen from the stern puts H toward the bow. A right turn corresponds to a precession vector downward (−z). The gyroscopic couple is C = Ω × H, giving a couple about the transverse axis that pitches the ship.
Vector resultΩ (down) × H (forward) acts about the negative transverse axis, tending to lower the bow and raise the stern.
Final AnswerRaise the stern and lower the bow