The table below gives the average temperature T at a depth d

The table below gives the average temperature, T, at a depth d, in a borehole in Belleterre, Quebec.

d, depth (m) 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300

T, temp (C) 5.50, 5.20, 5.10, 5.10, 5.30, 5.50, 5.75, 6.00, 6.25, 6.50, 6.75, 7.00

Evaluate T/d on the following intervals

a) 75 d 125 T/d =

b) 100 d 200 T/d =

c) 2 5 d 75 T/d =

Solution

a) 75 d 125, T/d

T/d =(5.30 - 5.10)/(125-75) = 0.004deg/mt

b) 100 d 200 T/d

T/d = (6.00 -5.10)/100 = 0.009 deg/mt

c) 2 5 d 75 T/d

T/d =(5.10 -5.50)/(50 ) = -0.008 deg/mt