旋回中の船のKinetic Energy
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概要
- 論文の詳細を見る
If a force F is applied to a body through a distance x, then the work done W by the force is defined as W=Fx. Newton's second law of motion states that if a force F is applied to a body of mass M, the body will undergo an acceleration α, according to the relation F=Mα. Thus the work done is just the difference in the value of the kinetic energy function 1/2MV^2, evaluated at the final and initial positions. Here V is the velocity of the body. It had always been thought that the mass of an object was basic to the body and in fact was an absolute constant. In Einstein's theory it is found that the mass of an object is dependent upon the travelling velocity. In disscussing the kinetic energy of a moving mass we did not take account of changes in the mass, that is, we discussed the case where the velocities are much less than the velocity of light and the increase in mass is negligible. In author's theorem it is found that if a constant gyrating moment Pl is applied on a vertical axis of midship through an angle from 0 to 1 radian, the ship will undergo an angular acceleration ω, according to the relation Pl=I〓 ω. Here I〓 is the moment of inertia for the sum of the ship's mass and the added gyrating water mass on the vertical axis of midship. But a water mass stuck to the ship which is a part of the added gyrating water mass is dependent upon the angular velocity ω, thus the time function of ω is the outcome of what has been inversely proportional to the time function of increase in mass. It is found that the kinetic energy of the gyrating ship is 0.72 I〓ω^2. The kinetic energy of a turning ship is 0.6 m_3I_0ω^2. Here I_0 is the moment of inertia for the sum of the ship's mass and the added gyrating water mass on the pivoting point of ship. m_3 is the coefficient of turning virtual moment of inertia. 0.6 is the mean coefficient of kinetic energies of turning ships.
- 社団法人日本船舶海洋工学会の論文
- 1974-12-30