An elementary treatise on kinematics and dynamics / by James Gordon MacGregor.

  • MacGregor James Gordon, 1852-1913.
Date:
1902
Catalogue details

Licence: In copyright

Credit: An elementary treatise on kinematics and dynamics / by James Gordon MacGregor. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    50/550 (page 32)
    by 57, employing a formula similar to that of 49, viz., a : 392 = 0-0003x60-: 1. Hence a = 392 x GO2 x 0-0003 kilom.-per-hour per hour. Otherwise, without using formulae, thus : 392 ft.-min. units of rate of change of speed = 392 ft.-per-min. per min. = 392 x 0-0003 kilom.-per-min. per min. = 392 x 0-0003 x 60 kilom.-per-hour per min. = 392 x 0-0003 x 60 kilom.-per-hour per hour. (7) Compare the foot sec. and the yd.-min. units of rate of change of speed. Ans. 1 ft.-sec. unit = 1,200 yd.-min. units. (8) How many cm.-sec. units of rate of change of speed in 1 ruile- min. unit 'I Ans. 44-704 (9) The rate of change of speed of a falling body (32*2 ft.-sec. units) and 1 pole (5^ yds.) being the units of rate of change of speed and of length respectively of a derived system, find the unit of time. [See 58 and 50 (9).] Ans. 0-7... sec. (10) The unit of speed of a derived system being the speed of a point in the earth's equator (the earth being supposed a sphere of 4,000 mis. radius), and the unit of time the month (30 days), compare the unit of rate of change of speed with the ft.-sec. unit. Ans. It is equal to 0-00059... ft.-sec. unit. (11) Eeduce 101 metre-min. units of rate of change of speed to cm.-sec. units. Ans. 2'8... cm.-sec. units. (12) Express (a) in cm.-sec. units, and (b) in kilom.-hour units, a rate of change of speed of 90 ft.-per-sec. per sec. Ans. (a) 2,743-17...; (h) 355,515-6.... 60. Motion under Given Rates of Change of Speed.— We have seen that the rate of change of speed of a point