51. Tres trabajadores levantan un piano de 3.50 kN con rapidez constante hasta un departamento a 25.0 m arriba de la calle utilizando un sistema de polea sujeto al techo del edificio. Cada trabajador puede suminis- trar 165 W de potencia y el sistema de polea es 75% efi- ciente (de manera que 25% de la energía mecánica se pierde debido a la fricción en la polea). Ignorando la masa de la polea, encuentre el tiempo requerido para subir el piano desde la calle al departamento.​

What elements are found in the inner and out core of the earth? the correct layers of earth's interior from the top to the center? what is the unwanted material that is removed from a mine called? how much stronger is an earthquake that registers 5 on the richter as opposed to 2? what occurs at a convergence plate boundary? the majority of the the earth's rock what is the most common element found in the earth's crust? what element is found in pyrite that contributes to acid mine drainage? why must mining companies post bond prior to permitting? how are bacteria being used in treating effluent from mines? what is a problem of acid mine drainage in rivers and soils? what do tectonic plates move on? why is gold smelting so damaging? how are artesian wells formed? where is dammed water colder than the river it flows into? what is one of the problems of uncontained aqueducts? what is the largest use of industrial water? underground sand and gravel formations that can store water? what type of water test measure acidity? which type of water test for cloudiness from suspended solids? what water test measures the amount of calcium and magnesium? these are all problems of coal power plants all of the following are advantages of riparian lands along rivers what type of water would be the warmest and have the least amount of dissolved oxygen? the zone of aeration is

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

In addition to gravity, what is the other predominant force that affects the motion of a pendulum?