A welding heat source is capable of transferring 150 Btu/min to the surface of a metal part. The heated area is approximately circular, and the heat intensity decreases with increasing radius as follows: 50% of the power is transferred within a circle of diameter = 0.1 in and 75% is transferred within a concentric circle of diameter = 0.25 in. What are the power densities in
(a) the 0.1-in diameter inner circle and
(b) the 0.25-in diameter ring that lies around the inner circle?
(c) Are these power densities sufficient for melting metal?