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yiki 發問於 科學及數學數學 · 1 十年前

Applied Maths.....

Particles of mass m and 2m are connected by a light string which passes over a pulley at the vertex of a wedge-shaped block, one particle resting on each of the faces which are smooth. The mass of the wedge being M, and the inclination of the faces to the horizontal being a, find the acceleration of the wedge and the particles when the wedge is placed on a smooth horizontal table.


The answer is (mg sin a cos a)/(M+3m(sina)^2)

1 個解答

  • 1 十年前

    I think it should be like this.

    Therefore, the acceleration

    = ( 2mg sin a cos a - mg sin a cos a ) / (M + m + 2m)

    = ( mg sin 2a ) / 2(M + 3m)

    2007-06-11 15:00:44 補充:

    Oh. I didn't consider the fact that the particles can move smoothly too on the wedge too. vertical component of acceleration of the small masses is = g (sin a)^2

    2007-06-11 15:00:52 補充:

    Therefore the effective masses (for calculating horizontal movement) of the 2 particles are m (sin a)^2 and 2m (sin a)^2 respectively.Hence your answer.