Specific gravity denotes the relative or comparative gravity of any body, in respect to that of another body of equal bulk, or magnitude.
Centre of gravity is that point in a body, or system of bodies, on which, if rested, or suspended, the whole would remain in a state of equilibrium about that point.
The centre of gravity of a circle, regular polygon, prism, cylinder, or sphere, is in its centre.
The centre of gravity of a triangle is found by bisecting any two of its sides, and drawing lines from the points of bisection to the opposite angles; the intersection of these lines will be the centre of gravity.
Force of gravity, or gravitation, is an accelerated velocity, which bodies acquire in falling freely from a state of rest.
1. The space through which a body will fall in feet, in any given time equals the product of the square of the time multiplied by 16·0833.
Example.—Required the space a falling body will pass through in five seconds?
16·0833 × 25 = 412·0825 feet.
2. The velocity in feet, which a body in descending freely will acquire in a given time, equals the product of the time in seconds multiplied by 32·1666.