Engineers' and mechanics' pocket-book .. by Haswell Charles Haynes 1809-

Engineers' and mechanics' pocket-book .. by Haswell Charles Haynes 1809-

Author:Haswell, Charles Haynes, 1809- [from old catalog]
Language: eng
Format: epub
Tags: Engineering, Mechanical engineering
Publisher: New York, Harper & brothers
Published: 1881-03-25T05:00:00+00:00


To Compute tlie Velocity- of a Falling Stream of Water per Second at tlie End. ofanj'- given Time, the perpendicular Distance "being given.

Example. —What is the distance a stream of water will descend oa an inclined plane 10 feet high, and 100 feet long at the base, in 5 seeonds ?

5 2 X16.083 =402.08 feet = the space a body will freely fall in this time.

Then, as 100 : 10:: 402.08 : 40.21 feet = the proportionate velocity on a plane of these dimensions to the velocity when falling freely.

Tlie various Formulas here given are for Bodies Projected Upwards or Falling Freely, in Vacuo.

When, however, the weight of a body is great compared with its volume^ and the velocity of it is low, deductions given are sufficiently accurate for ordinary purposes.

ANIMAL STRENGTH.

The mean effect of the power of a man v unaided by a machine, working to the best practicable advantage, is the raising of 70 lbs. 1 foot high in a second, for 10 hours in a day.

Two men, working at a windlass at right angles to each other, can raise 70 lbs. more easily than one man can 30 lbs.

The result of observation upon animal power furnishes the following as the maximum daily effect :

1. When the effect produced varied from % to .2 of that which could be produced without velocity during a brief interval.

2. When the velocity varied from % to % for a man, and from .08 to .06G for a horse, of the velocity which they were capable for a brief interval, and not producing any effort.

3. When the duration of the daily work varied from ^ to ^ for a brief interval, during which the work could be constantly sustained without prejudice to the health of the man or the animals; the time not extending beyond 18 hours per day, however limited may be the daily task, so long as it represents a constant attendance in the shop.

By Mr. Field's experiments in 1838, the maximum power of a strong man, exerted for 2>£ minutes z= 18000 lbs. raised one foot in a minute.

A man of ordinary strength exerts a force of 30 lbs. for 10 hours in a day, with a velocity of 2^ feet in a second == 4500 lbs. raised one foot in a minute = .2 of the work of a horse.

A man can travel, without a load, on level ground, during 8>£ hours a day, at the rate of 3.7 miles an hour, or 31^ miles a day. He can carry 111 lbs. 11 miles in a day. Daily allowance of water for a man, 1 gallon for all purposes; and he requires from 220 to 240 cubic feet of air per hour.

A porter going short distances, and returning unloaded, can carry 135 lbs. 7 miles a day. He can transport, in a wheelbarrow, 150 lbs. 10 miles in a day.

The muscles of the human jaw exert a force of 534 lbs.

Mr. Buchanan ascertained that, in working a pump,



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