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Anonymous
Anonymous asked in 科學其他:科學 · 1 decade ago

急需!!! 請問這題物理要怎麼解? (英文的)

As your bus rounds a flat curve at constant speed, a package with mass 0.300kg , suspended from the luggage compartment of the bus by a string 50.0 cm long, is found to hang at rest relative to the bus, with the string making an angle of 30.0(degree) with the vertical. In this position, the package is 55.0 m from the center of curvature of the curve.

What is the speed of the bus?

1 Answer

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  • 提姆
    Lv 5
    1 decade ago
    Favorite Answer

    離心力使懸掛物體偏離30度角

    1、利用偏離30度角算出離心力F的大小

      F/W=tan30度

      =>F=W*tan30=mg*1/√3=mg(√3/3)

    2、利用已知的半徑與離心力求切線速度

      F=mv^2/r

      mg(√3/3)=mv^2/r

      v=√(gr(√3/3))=√(9.8*55*√3/3)=17.64m/s=63.5km/hr

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