Question Details

The figure shows an arrangement of a heavy propeller shaft in a ship. The combined polar mass moment of inertia of the propeller and the shaft is 100 kg.m2. The propeller rotates at ω = 12 rad/s. The waves acting on the ship hull induces a rolling motion as shown in the figure with an angular velocity of 5 rad/s. The gyroscopic moment generated on the shaft due to the motion described is ______ N.m. (round of to the nearest integer).

Show Answer

Correct Answer :

Correct answer is : 6000

l = 100 kgm2

ω = 12 rad/s

ωp = 5 rad/s

Gyroscopic couple 100 x 12 x 5 = 6000 Nm

Solution :

The correct answer is 6000.

Analysis of the Figure and Motion:
The provided image shows two views of the ship's propeller shaft assembly:
1. The Side view shows the propeller attached to a horizontal shaft aligned along the z-axis (axis of spin). The propeller and shaft rotate with an angular velocity ω about this axis.
2. The End view shows the "Ship hull" facing front-on, with the vertical y-axis and horizontal x-axis. It depicts a "Rolling" motion of the ship's hull about the longitudinal z-axis (the axis of the propeller shaft) represented by a curved arrow, with a rolling angular velocity ωp.

Given Data:
- Combined polar mass moment of inertia of the propeller and shaft, I=100 kg·m2
- Propeller spin velocity, ω=12 rad/s
- Rolling angular velocity (precession velocity in this context), ωp=5 rad/s

Calculation of the Gyroscopic Moment:
The magnitude of the gyroscopic moment (or gyroscopic couple) T generated on the shaft is given by the formula:

T = I ω ω p
Substituting the given values into the formula:

T = 100 12 5
T = 6000 N·m
Therefore, the gyroscopic moment generated on the shaft due to the described motion is 6000 N·m.

Unlock Our Free Library

Access expert-curated educational resources and study materials—completely free.

Ask AI Tutor
5 left
Q1 View Question & Options
AI Tutor is solving this question...
Reading question context & options...