Question

an engineering student is studying specific applications of liquid nitrogen. the temperature of the material in degrees celsius, y, can be modeled by the following graph, where x represents the time, in hours, since the treatment began. temperature of material which of the following statements are true for this situation? a. the materials initial temperature is -30 degrees celsius. b. the material returned to its initial temperature after 40 hours. c. the materials temperature reaches a minimum at 15 hours.

Explanation:

Step1: Find initial temperature

When \(x = 0\), from the graph, \(y=0\), so the initial - temperature is 0 degrees Celsius, so option A is false.

Step2: Check temperature at 40 hours

When \(x = 40\), \(y
eq0\), so the material did not return to its initial temperature after 40 hours, option B is false.

Step3: Locate minimum - point

The lowest point of the graph occurs at \(x = 15\) hours. At this time, the material's temperature reaches a minimum. So option C is true.

Answer:

C. The material's temperature reaches a minimum at 15 hours.