The iron block had a mass of 2 kg. Calculate the energy transferred by the heater to increase the temperature of
the iron block by 5 °C.
The specific heat capacity of iron is 450 J/kg °C.

While carrying a heavy box up the stairs, you set the box on a step and rest. then you pick up the box and carry it to the top of the stairs. describe these actions in terms of balanced and unbalanced forces acting on the box.