This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1848 Excerpt:...it is done. For, let H be the number of horses power consumed in performing U units of work, and let T be the number of minutes in which this work is performed; then 33,000 HT= U; U 33,000 T " Suppose a body to pass from the velocity V to the W velocity Vt, then, the vis viva being--F', the work accumulated in passing from the velocity V to the velocity V, will be W W W Here we have supposed that the motion is accelerated, or that Vt is greater than V; but if, on the contrary, the velocity V, be less than V, or the motion be retarded, then the work lost will be W hence, if U represent the number of units of work accumulated or lost, we have. u=±i?(r;-r)... (4) The upper sign must be used when the motion is accelerated, and under sign when the motion is retarded. This evidently applies to the case where a body is projected either downwards or upwards with a given velocity; the work done, in the former case, is 93. To estimate the work in the case where the pressure is not exerted in the direction in which the space is described. Suppose the point of application Q of the pressure to traverse the line AB, the pressure being constantly exerted, not in the direction from A towards B, but in a direction which is always parallel to the line MQ; then will the work done while Q is moving from A to Q be the same as though the point of application, instead of moving from A to Q, had moved along the line MQ, from M to Q; QM being the projection of AQ upon the direction of the pressure; so that the work done would be represented by P x MQ; P being the pressure in lbs., and MQ the space in feet. For, resolve P into two forces, one perpendicular, and the other parallel to AB; as no motion takes places in the perpendicular direction, no work is done in that direc...