A 3.30-kN piano is lifted by three workers at a constant speed to an apartment 28.8 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 197 W of power, and the pulley system is 75.0% efficient (so that 25.0% of the mechanical energy is lost due to friction in the pulley). Neglecting the mass of the pulley, find the time required to lift the piano from the street to the apartment.

  1. 👍 0
  2. 👎 0
  3. 👁 352
  1. mg=3300 N, h=28.8 m, Pₒ=197 W

    PE =mgh
    E= mgh/0.75
    P=E/t = mgh/0.75•t = 3•Pₒ
    t= mgh/0.75•3• Pₒ =
    =3300•28.8/0.75•3•197 =
    = 214 s =3.57 min

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics

    a 300kg piano is being lifted at a steady speed from ground level straight up to an apartment 10.0m above ground. The crane that is doing the lifting produces a steady power of 400 W. How much time does it take to lift the piano?

  2. Intro Physics - Newton's third rule

    a piano mover raises a 1000 N piano at a constant speed using a very light rope in a frictionless pulley system. with what force is the mover pulling down on the rope? Show steps please! Thank you!

  3. math

    Nathan and Steven stacked boxes on a shelf. Nathan lifted 13 boxes and Steven lifted 15 boxes. The boxes that Nathan lifted each weighed 12 lb more than the boxes Steven lifted. Which expression represents the total number of

  4. physics

    in a daring rescue by helicopter, two men with a combined mass of 172 kg are lifted to safety. a)If the helicopter lifts the menstraight up with constant acceleration, is the tension in the rescue cablegreater than, less than, or

  1. physics

    20.) A piano has been pushed to the top of the ramp at the back of a moving van. The workers think it is safe, but as they walk away, it begins to roll down the ramp. If the back of the truck is 1.5 above the ground and the ramp

  2. Physical Science

    Two objects were lifted by a machine. One object had a mas of 2 kilograms, and was lifted at a speed of 2 m/sec. The other had a mass of 4 kilogram was lifted at a rate of 3 m/sec. ------------------------------------------- a)

  3. science

    Three people push a piano on wheels with forces of 130 N to the right, 150 N to the left, and 165 N to the right. What is the strength and direction of the net force on the piano?

  4. statitstics

    A warehouse employs 22 workers on first shift and 14 workers on second shift. Eight workers are chosen at random to be interviewed about the work environment. Find the Probability of choosing: A. All first-shift workers B. All

  1. Physics

    A man pushes on a piano of mass 180 kg so that it slides at a constant velocity of 12.0 cm/s down a ramp that is inclined at 11.0degrees above the horizontal. No appreciable friction is acting on the piano. Calculate the magnitude

  2. physics

    A 7.5-kg box is being lifted by means of a light rope that is threaded through a single, light, frictionless pulley that is attached to the ceiling. If the box is being lifted at a constant speed of 2.0m/s, what is the power

  3. science

    Which type of mechanical energy do the following contain? Kinetic Energy, Potential Energy, or Both A Car traveling at 100 mph along a flat road - KE A rubber band that has been stretched - PE A bowling ball rolling down a lane -

  4. Physics

    You and your friend throw balloons filled with water from the roof of a several story apartment house You simply drop a balloon from rest. A second balloon is thrown downward by your friend 2.1seconds later with an initial speed

You can view more similar questions or ask a new question.