蔥頭 asked in 科學其他:科學 · 1 decade ago

大一物理作業問題需要幫忙

有兩題需要幫忙 需要解法與答案

A block of mass m1=3.70kg on a angle 30.0度 is connected by a cord over a massless, frictionless pulley to a second block of mass m2=2.30kg. What are (a)the magnitude of the acceleration of each block, (b) the direction of acceleration of the hanging block, and (c) the tension in the cord?

Three connected blocks are pulled to the right on a horizontal frictionless table by a force of magnitude T3 = 65.0 N.If m1 = 12.0kg, m2 = 24.0kg, and m3 = 31.0kg, calculate (a) the magnitude of the system's acceleration,(b) the tension T1, and (c) the tension T2

兩題都有圖 但是我不知道怎麼掛上去

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拜託謝謝

1 Answer

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  • 1 decade ago
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    Taking g = 10 m/s2.

    (1) Component of weight of m1 in parallel to the inclined plane = 3.7 x 10 sin 30 = 18.5 N

    Weight of m2 = 23 N

    So net force on the whole system = 23 - 18.5 = 4.5 N

    (a) Acceleration = 4.5/(3.7 + 2.3) = 0.75 m/s2

    (b) Direction of acceleration of the hanging block is downward.

    (c) Consider the acceleration of the hanging block:

    2.3 x 10 - T = 2.3 x 0.75

    T = 21.28 N

    (2a) Total mass = 12 + 24 + 31 = 67 kg

    So acceleration = 65/67 = 0.97 m/s2.

    (b) T1 is responsible forpulling m1 and so T1 = 12 x 0.97 = 11.6 N

    (c) T2 is responsible forpulling m1 and m2 and so T2 = 36 x 0.97 = 34.9 N

    Source(s): Myself
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