Where Gravity rely's on only mass and distance and nothing else, so the weight on the planets will vary like you have stated. However Mars is smaller than Mercury, so the weight on Mars will be less, and the weight on Mercury will be more. Think this way.
More Mass = More Gravity = More Weight
Less Mass = Less Gravity = Less Weight
Temperature - The measure of the average kinetic energy of a substance
Internal Energy - Total potential and kinetic energies of the particles of a substance
Heat - Thermal energy that flows from one substance to another
Thermal Energy - Part of internal energy that can be transferred
Power = energy / time
Time should be in seconds
5 hours = 5 × 60 minutes = 5 × 60 ×60 seconds = 18000 s
Power = 6000/18000 = 0.333 W
Hope it helped!