Suppose that the rod in Fig. 17.24a is made of copper, is 45.0 cm long, and has a cross-sectional area of 1.25 cm2. Let TH = 100.0°C and TC = 0.0°C. (a) What is the final steady-state temperature gradient along the rod? (b) What is the heat current in the rod in the final steady state? (c) What is the final steady-state temperature at a point in the rod 12.0 cm from its left end?

a) 222k/m

b) 42.5W

c) if cold: 26.7C

If hot: 73.3C

Explanation:

 If TH and TC are at the ends of the rod in the figure, then;

(A) 100 K / 45 cm = 2.22 K/cm or 222 K/m

(B) thermal conductivity constant for copper is 390 W/(m K).

Then the heat flow rate = Q/t

Q/t = [390 W/(m K)] (100 K) [ pi (0.0125 m)^2 ] / (0.45 m) 

= 42.5 watts

(C) 12/45 = 4/15 = 0.2667

If the left end is the cold end, the answer will be 26.7 C

If the left end is the hot end, the answer will be 73.3 C

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.

0.93xc=0.93x3x10^8m/s

2.54cm is 1 inch

360seconds i 1 hr