A load of 400 N is lifted by a first class lever in which the load is at the distance of 20 cm and the effort is at the distance of 60 cm from fulcrum If150 N effort is required to lift the load what is its efficiency

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.

An ice-making machine inside a refrigerator operates in a carnot cycle. it takes heat from liquid water at 0.0 degrees celsius and rejects heat to a room at a temperature of 19.2 degrees celsius. suppose that liquid water with a mass of 76.3kg at 0.0 degrees celsius is converted to ice at the same temperature. take the heat of fusion for water to be l_f = 3.34*10^5 j/kg.how much energy e must be supplied to the device? express your answer in joules.