You and two friends are planning on lifting a 3.25 kN piano at constant speed to your apartment 26.0 m above the street level using a pulley system fastened to the roof of the building. Each of you is able to deliver energy at the rate of 160 W by doing work on the rope of a pulley system that is 75.0% efficient. That is, 25.0% of the energy is transformed to other forms due to friction in the pulley. You wish to block off the sidewalk to protect pedestrians while you raise the piano, but are worried because it is a busy street and you may get in trouble with local authorities if you block the sidewalk too long. For what time interval (in min) will the sidewalk be blocked while the piano is moving upward

An charge with mass m and charge q is emitted from the origin, (x,y)=(0,0). a large, flat screen is located at x=l. there is a target on the screen at y position y(h), where y(h) > 0. in this problem, you will examine two different ways that the charge might hit the target. ignore gravity in this problem. 1.assume that the charge is emitted with velocity v(0) in the positive x direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive y direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l. 2.now assume that the charge is emitted with velocity v(0) in the positive y direction. between the origin and the screen, the charge travels through a constant electric field pointing in the positive x direction. what should the magnitude e of the electric field be if the charge is to hit the target on the screen? express your answer in terms of m, q, y(h), v(0), and l.