Handbook of Railroad Construction; For the use of American engineers. / Containing the necessary rules, tables, and formulæ for the location, construction, equipment, and management of railroads, as built in the United States.

by George L. Vose

Given the space fallen through, to find the velocity.

√height in feet × 64.3 = velocity in feet per second.

Thus the velocity of a body falling twenty feet will be

√20 × 64.3 = 36 feet per second.

Momentum is the product of weight by velocity; therefore, to find the force of the blow given by a ram of given weight, falling a given height, we find, first, the velocity by rule two. Also, given the weight of ram, the necessary velocity to produce any required effect being found, it is easy to find the height, and the reverse.

Examples.—Suppose we have a ram weighing 2,000 lbs. and wish to strike a blow of 25,000 lbs.; the velocity must be

25000
2000 = 12½ feet per second;

and to acquire that velocity, the height fallen must be (rule one)

(12½
8)² = 2.43 feet.

Again, if we have a pile-engine which admits of a fall of fifteen feet, and we wish to strike a blow of 18,000 lbs., we first find the velocity (rule two) thus:—