A manual of physics, theoretical and practical : for medical students / by Hugh C. H. Candy.

  • Candy, Hugh Charles Herbert, 1859-1935
Date:
1918
Catalogue details

Licence: In copyright

Credit: A manual of physics, theoretical and practical : for medical students / by Hugh C. H. Candy. Source: Wellcome Collection.

    58/470 (page 44)
    the pulleys are movable, string passes round each except one. A separate movable pulley (a^, etc.), and is attached at one end to the beam. It is clear that, if all the strings remain taut, when w ascends a dis¬ tance h, AI must ascend Ji, and, there¬ fore, the string on each side of A^ must shorten by ]i, which means that a length of string = 2h must be passed round, and therefore a 2 must ascend 2h. Similarly, Ao must ascend 2 X 2h = 2H. A 4 must ascend 2 X 2'^li ^ 2% and P must descend 2 X 2^1i = 2%. Hence by the equation of work— W Xh =P'X 2% W 24 Similarly, if there are n movable pulleys, we shall have Fig. 18.—Second system of pulleys. P T (c) In the third system of pulleys (Fig. 19), a separate string passes round each pulley, and is