The Motion of Fluids and Resistance to Projected Bodies on Superphysics

Cylindrical Motion

Mon, 01 Jan 0001 00:00:00 +0000

PROPOSITION 37 THEOREM 29

A cylinder moves uniformly forwards in a compressed, infinite, and non-elastic fluid, in the direction of its length.

The arising resistance is to the force by which its whole motion may be destroyed or generated, in the time that it moves 4 times its length, as the density of the medium to the density of the cylinder, nearly.

Resistance of Globes

Mon, 01 Jan 0001 00:00:00 +0000

Assume that a globe moves uniformly forward through a fluid enclosed and compressed in a cylindric canal.

Its resistance is to the force by which its whole motion may be generated or destroyed in the time in which it describes eight third parts of its diameter.

Resistance of Globes Problem

Mon, 01 Jan 0001 00:00:00 +0000

Find by phænomena the resistance of a globe moving through a perfectly fluid compressed medium.

Let A be the weight of the globe in vacuo, B its weight in the resisting medium, D the diameter of the globe, F a space which is to 4/3D as the density of the globe to the density of the medium, that is, as A to A - B, G the time in which the globe falling with’ the weight B without resistance describes the space F, and H the velocity which the body acquires by that fall.

Resistance of Globes Problem

Mon, 01 Jan 0001 00:00:00 +0000

Experiment 5: Four globes, weighing 1541/8 grains in air, and 21½ grains in water, being let fall several times, fell in the times of 28½, 29, 29½, and 30, and sometimes of 31, 32, and 33 oscillations, describing a height of 15 feet and 2 inches.

They ought by the theory to have fallen in the timeos 29 oscillations, nearly.

The Resistance of Globes

Mon, 01 Jan 0001 00:00:00 +0000

If a globe moves uniformly forward in a compressed, infinite, and non-elastic fluid, its resistance is to the force by which its whole motion may be destroyed or generated in the time that it describes eight third parts of its diameter, as the density of the fluid to the density of the globe, very nearly.