- The rate at which work is done on a particular axle is measured by the product where T is the torque or turning moment exerted on the axle by the motor or mechanism applied to it for this purpose, and is the angular velocity of the axle in
**radians**per second. - Diameter, w = 44/2 = 22
**radians**per second, and therefore T= 440,000/22=20,000 lb ft. - If the speed is given in miles per hour, S say, V =1.466 S (6) The revolutions of the axle per second, n, are connected with the
**radians**turned through per second by the relation n =w/27r = w/6.38 (7) § 2. - The general theory of this kind of brake is as follows: - Let F be the whole frictional resistance, r the common radius of the rubbing surfaces, W the force which holds the brake from turning and whose line of action is at a perpendicular distance R from the axis of the shaft, N the revolutions of the shaft per minute, co its angular velocity in
**radians**per second; then, assuming that the adjustments are made so that the engine runs steadily at a uniform speed, and that the brake is held still, clear of the stops and without oscillation, by W, the torque T exerted by the engine is equal to the frictional torque Fr acting at the brake surfaces, and this is measured by the statical moment of the weight W about the axis of revolution; that is T =Fr=WR... - The ratio p is given by e"` e, where e= 2.718; µ is the coefficient of friction and 0 the angle, measured in
**radians**,, subtended by the arc of contact between the rope and the wheel.

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