El paquete de 50 lb que se muestra en la figura parte desde el reposo, se desliza hacia abajo sobre la rampa y es detenido por el resorte. El coeficiente de fricción cinético entre el paquete y la rampa es μk = 0.12. Si se desea que el paquete llegue al reposo a pulgadas del punto de contacto, que valor debe tener la constante k del resorte?.

Suppose that a cylindrical tank 6 meters high with a radius of 2 meters is filled to the rim with water. the tank is buried so that the top of the tank is 1 meter below ground level. the space above the tank is not filled with water. calculate how much work needs to be done by a pump to pump the water out of the tank up to ground level. (the water weighs 9,800 newtons per cubic meter.)