崔屁屁 發問時間: 科學其他:科學 · 1 0 年前

At time t = 0 a particle start

At time t = 0 a particle starts moving along the x axis. If its kinetic energy increases uniformly with t the net force acting on it must be:

A. constant

B. proportional to t

C. inversely proportional to t

D. proportional to 根號t

E. proportional to 1/根號t

1 個解答

評分
  • 阿煜
    Lv 5
    1 0 年前
    最佳解答

    Answer:E

    *The answer image file can't be upload to here now!

    2009-11-03 04:38:38 補充:

    k,c=const.

    T=kt=(0.5)mv^2 kinetic energy

    v=(2kt/m)^0.5 speed_function of t

    F=ma=m(dv/dt)=(k(2k/m)^(-0.5))t^(-0.5)

    c=k(2k/m)^(-0.5)=const.

    F=ct^(-0.5)

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