Читать книгу The Practice of Engineering Dynamics - Ronald J. Anderson - Страница 22

1 1 The convention used here is that a vector with an overdot such as is used to represent the rate of change of magnitude of the vector and the overdot is not to be interpreted as a shorthand method of signifying the total derivative of the vector. For a scalar function there is only a magnitude and the overdot will represent its rate of change.

2 2 Let the cross product of two vectors, and , be the vector, According to the right hand rule, the direction of is the direction aligned with the thumb of your right hand if you point that hand in the direction of and curl your fingers towards .

3 3 Three dimensional sets of unit vectors shown in two dimensional figures such as Figure 1.3 will be shown with the positive sense of the vector out of the plane represented by a curved arrow using the right hand rule (e.g. in Figure 1.3).

4 4 Readers are encouraged to review the rules for cross multiplication of vectors.

5 5 Gaspard Gustave de Coriolis (1792–1843), an engineer and mathematician, introduced the terms “work” and “kinetic energy” to engineering analysis but is best remembered for showing that the laws of motion could be used in a rotating reference frame if an extra term called the Coriolis acceleration is added to the equations of motion.