Final answer:
Without the mass and specific heat capacity of the cylinder, it is not possible to accurately calculate the final temperature of the coffee when a cylinder at -20°C is placed into it.
Step-by-step explanation:
To calculate the change in temperature when a cylinder cooled to -20°C is dropped into 500g of coffee at 85°C, we need to apply the concept of heat transfer and thermal equilibrium. The principle of conservation of energy dictates that the heat lost by the hot object (coffee) will equal the heat gained by the cold object (cylinder) until thermal equilibrium is reached. However, to provide a specific answer, we need the mass and the specific heat capacity of the cylinder, which are not provided in the question. Without these pieces of information, we cannot calculate the final temperature of the coffee accurately.