Two blocks are connected by a string over a frictionless pulley. Find acceleration of the blocks and the tension of the strings. ?

Assume the string is weightless.

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  • NCS
    Lv 7
    1 month ago
    Favorite Answer

    net force = motive force - resistive force

    Fnet = weight on incline - friction on incline and horizontal

    Fnet = [2.0kg*sin30º - 0.14*(2.0kg*cos30º + 0.80kg)] * 9.8m/s²

    Fnet = 6.33 N

    acceleration a = Fnet / M = 6.33N / 2.8kg = 2.26 m/s² ◄

    which ought to be rounded to 2.3 m/s² imo

    consider the top mass

    Fnet = T - f

    0.80kg * 2.26m/s² = T - 0.14*0.80kg*9.8m/s²

    and so

    tension T = 2.9 N ◄

    Hope this helps!

  • oubaas
    Lv 7
    1 month ago

    Moving force MF = 2*g*sin 30° = 9.807 N

    resistent force RF = g*μk*(0.8+2*cos30°) = 9.807*0.14*(0.8+2*0.866) = 3.477 N

    accelerating force AF = MF-RF = 6.33 N 

    acceleration a = AF/(m1+m2) = 6.33/2.8 = 2.26 m/sec^2 

    tension T = 0.8*(9.807*0.14+2.26) = 2.91 N

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