Newton's Law of Cooling The temperature of an object is the temperature of the object and its surroundings (ambient). It means that the temperature changes proportionally with the difference between: ( ) In this equation, T: temperature of the object (C), t: time (minute), k: proportionality coefficient (1/minute), and Ta: ambient temperature (C). Euler's Method determines what the temperature of a cup of coffee at 68 C will be after 10 minutes. and calculate the time interval (step size) by 1 minute. Ta = 21 C and k=0.1/min