speed

A cargo of 50 kg is raised at a steady speed of 0.5ms^-1 for 5s .Suddenly the cable breaks and the crgo falls onto the ground .

a)sketch a graph to show hpw the potential energy of the cargo changes with time in the first 10s . take the ground as the reference level .

b)Estimate the speed of the cargo just before it hits the ground .

Update:

sorry..

a)唔使做

Update 2:

sorry,,

b)已經識做

不過有另一條比較簡單既問題讓大家解答=}

A catapult of an aircraft carrier can accelerate an F-18 jet fighter of mass 16000kg from rest to 64ms^-1 with an average acceleration of 32ms^-2 along a straight line . Find the average power delivered to the jet .

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  • 1 decade ago
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    Time for the catapult to accelerate the fighter from rest to 64ms^-1

    = (64-0)/32 = 2 seconds

    Increase of kinetic energy of fighter from rest to 64ms^-1

    =(1/2)(16000)(64)^2

    = 32768000 J

    Therefore, average power delivered from the catapult to the jet fighter

    = 32768000J / 2 seconds

    =16.384MW

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