Energy
The mechanical work done by an external agent on a system is equal to the change in kinetic energy of the system:
- General work-energy theorem (translation and rotation)
The work done W by an external agent which exerts a force F (at r) and torque τ on an object along a curved path C is:
where θ is the angle of rotation about an axis defined by a unit vector n.
- Kinetic energy
- Elastic potential energy
For a stretched spring fixed at one end obeying Hooke's law:
where r2 and r1 are collinear coordinates of the free end of the spring, in the direction of the extension/compression, and k is the spring constant.
Read more about this topic: List Of Equations In Classical Mechanics
Famous quotes containing the word energy:
“I have witnessed the tremendous energy of the masses. On this foundation it is possible to accomplish any task whatsoever.”
—Mao Zedong (1893–1976)
“While the State becomes inflated and hypertrophied in order to obtain a firm enough grip upon individuals, but without succeeding, the latter, without mutual relationships, tumble over one another like so many liquid molecules, encountering no central energy to retain, fix and organize them.”
—Emile Durkheim (1858–1917)
“Violence among young people ... is an aspect of their desire to create. They don’t know how to use their energy creatively so they do the opposite and destroy.”
—Anthony Burgess (b. 1917)