Final answer:
The object with a higher temperature has more thermal energy. Heat transfers from the hotter to the colder object until thermal equilibrium is reached.
Step-by-step explanation:
If two objects have the same mass but different temperatures, the one with the higher temperature has more thermal energy. This is because thermal energy is a measure of the total kinetic energy of the particles in an object, which increases with temperature. When two bodies at different temperatures come into contact, the heat will flow from the hotter to the colder object until thermal equilibrium is reached, with no net energy transfer occurring once equilibrium is established.