A box of mass 3.6 kg is lifted 5.4 m above the ground. What is the change in energy in lifting
the box to this height?

So, the energy change that occurs is 190.512 J.

Hello ! I am Deva from Indonesia will help you regarding energy and its transformation. In this case, it's the use of energy from the lifter to be equivalent to the change in the object's potential energy. Why potential energy? Because the box undergoes a change in height and the potential energy specializes at a certain height. Work (W) due to change in potential energy () can be realized in the equation :

With the following condition :

We know that :

What was asked :

Step by step :

So, the energy change that occurs is 190.512 J.

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000