B) Heat exchange will stop as the two object acquire the same temperature.
Explanation:
A) When one hot object and one cold object are kept in contact then the heat is transferred from the hot object to the cold object via different modes of heat transmission. Hence, the cold object starts getting hot
B) The transmission of heat from the hot object to the cold object will stop as the temperature of the two object becomes equal to each other.
First you need to find the initial x component which is 13.02. After that you plug it into the 3rd formula on the AP physics formula sheet. Then rearrange it into the quadratic formula and solve for time. The answer should be 4.1 seconds.