The elements of thermal chemistry / by M.M. Pattison Muir ; assisted by David Muir Wilson.
- M. M. Pattison Muir
- Date:
- 1885
Licence: Public Domain Mark
Credit: The elements of thermal chemistry / by M.M. Pattison Muir ; assisted by David Muir Wilson. Source: Wellcome Collection.
29/338
![the body whose mass is m, while that body moves through the space s, in the same direction as that in which the force is applied. But when work is done on a body that body gains energy. In the case before us this gain of energy is attended with an increase of tlie velocity of the body, and the energy gained is measured by half the product of the mass into the difference between the squares of the final and initial velocities. This form of energy which is connected with the motion of a body, or system of bodies, is called kinetic energy, and is to be distinguished from j)otential energy, which is the energy con- nected with the configuration of the parts of a body or system of bodies. If the force F acted on the body with mass m in a direction opposite to the motion, then the force would act as a resistance to be overcome by the moving body. In this case the kinetic energy of the body would be decreased until the body came to rest, when the whole work done by it would be equal to the whole kinetic energy which it possessed when the force began to acth man But on tie weight, know the mass ^ in the movement of the [round to its ^int of rest rvhich the weight has keen nent to have been nnifonn tingr^ s=space, SECT. II. § 11.] FORCE AND ENERGY. 7 From this equation we can find the space through whicn the weight has been moved by the application of the force i acting for the time t. The time t is very small, therefore we may take the average velocity during this time as the arith- metical mean of the velocities at the beginning and end of the time, that is, as + ^')- But as space described is equal to velocity into time, it follows that s = ^ (v + w') t Then multiplying together the two equations we get Fts=^lm {v^-F)t-, and dividing by t, we have Fs = ^mv^ ,11 ol i'. > If the time during which the force acts is not so short that the mean velocity may be considered as equal to the aritlimctical mean of the velocities at](https://iiif.wellcomecollection.org/image/b28065050_0029.jp2/full/800%2C/0/default.jpg)
