Aforklift holds a 500 kg box 4 m in the air for 100 s. what is the minimum power required by the forklift

First of all, we need to calculate the work done by the forklift to lift the box of 500 kg by 4 meters. The work done is equal to the variation of gravitational potential energy of the box, given by:

where m=500 kg is the mass of the box,  and  is the variation of height of the box. Substituting these data into the equation, we find the work


And now we can calculate the minimum power required by the forklift, which is equal to the ratio between the work done and the time taken:

Magma  is composed of molten rock and is  stored  in the earth's crust. lava is  magma  that reaches the surface of our planet through a volcano vent.