A3.20-kn piano is lifted by three workers at a constant speed to an apartment 20.8 m above the street using a pulley system fastened to the roof of the building. each worker is able to deliver 179 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.
Answers: 3
Physics, 21.06.2019 22:30
Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.
Answers: 1
Physics, 21.06.2019 23:30
Two technicians are discussing a resistance measurement between the can-h and can-l wires. technician a says this measurement should be done with the ignition switch in the "run" position. technician b states that a measurement of 0 ohms indicates an open in the network. which technician is correct?
Answers: 3
A3.20-kn piano is lifted by three workers at a constant speed to an apartment 20.8 m above the stree...
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