Question

Question 1 A hot baked potato will cool faster if a person blows warm (body temperature) air on it instead of letting it cool naturally at room temperature. True False Question 2 Hot engine oil flows over a flat plate. Based on the velocity of the oil, the length of the plate, and the kinematic viscosity of the oil, the Reynolds number at the end of the plate is calculated to be 3.5 x 10^5. This Reynolds number tells us that the flow over the plate is laminar. True False

Answer 1

Answer and Explanation:

Question 1: False

A hot baked potato will cool faster if it is left to cool naturally at room temperature rather than if a person blows warm (body temperature) air on it. This is because blowing warm air on the potato would actually add heat to the system, slowing down the cooling process. When left at room temperature, the potato will transfer heat to the surroundings through conduction, convection, and radiation, leading to faster cooling.

Question 2: False

A Reynolds number of 3.5 x 10^5 indicates that the flow over the flat plate is not laminar, but rather turbulent. The Reynolds number is a dimensionless value used to predict the flow regime based on fluid velocity, characteristic length, and fluid properties like kinematic viscosity. In this case, a Reynolds number of 3.5 x 10^5 indicates turbulent flow, where the fluid exhibits chaotic and irregular motion.