Hello, i have a simple question regarding a problem im solving. Here it is: A 4x4m flat plate maintained at a constant temperature of 80 degree Celsius subjected to parallel flow of air at 1 atm,20 degree celsius and 10m/s.The total drag force acting on the UPPER surface of plate is measured to be 2.4N.Using heat momentum transfer analogy,determine the average convection heat transfer coefficient and the rate of heat transfer between the UPPER surface of the plate and air. I had the solution for this problem , however what i dont understand is that why is the total surface area used in the calculations 32(Which means both sides of the plate) WHEN it is clearly stated in the question that only the UPPER surface is involved. Can anyone enlighten me why is both sides of the plate used even though they said total drag force on the UPPER surface of plate is 2.4N and want us to determine the rate of heat transfer between the UPPER surface of plate and air. In my case i used 16 for surface area and subsequently got the wrong answers.