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Homework Help: Work and Power related Problem

  1. Oct 25, 2015 #1
    1) A box of 20 kg mass is pulled by force F with constant velocity on a horizontal surface. If force of friction is 49N, work done during displacement of 10m is ________ J.

    (a) 490
    (b) 245
    (c) 980
    (d) zero

    W= change in kinetic energy
    W=0 (constant velocity)

    Which equation will be used?

    2) Engine of a car of mass 1500 kg keeps car moving with constant velocity 5m/s. If frictional force is 1000 N, power of engine is ____________
    (a) 5 kW
    (b) 7.5 kW
    (c) 15 kW
    (d) 75 kW

    p=mv (momentum)

    Which answer in the above question?

    Please reply as early as possible.

  2. jcsd
  3. Oct 25, 2015 #2
    Did you try it yourself?
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