A champion weight lifter raises a 240 kg barbell a distance of 2.1 m. How much potential energy has

the barbell gained?

1 Answer

  • Answer:

    Your answer is below …….


    25. Brutus, a champion weightlifter, raises

    240 kg of weights a distance of 2.35 m.

    a. How much work is done by Brutus

    lifting the weights?


    = (240 kg)(9.80 m/s2)(2.35 m)

    = 5.5 x 103j

    b. How much work is done by Brutus

    holding the weights above his head?

    d=0, so no work

    c. How much work is done by Brutus

    lowering them back to the ground?

    d is opposite of motion in part a, so

    W is also the opposite, -5.5 x 103 J.

    d. Does Brutus do work if he lets go of

    the weights and they fall back to the


    No. He exerts no force, so he does

    no work, positive or negative.

    If Brutus completes the lift in 2.5 s.

    how much power is developed?

    * = multiply

    [tex]P = \frac{W}{t} = \frac{5.53 * 10x^{3} J}{2.5s} = 2.2 kW[/tex]


    (Hope this helps can I pls have brainlist (crown)☺️)