Question
1. A firewalker runs across a bed of hot coals without sustaining burns. Calculate the heat transferred by conduction into the sole of one foot of a firewalker given that the bottom of the foot is a 3.00-mm-thick callus with a conductivity at the low end of the range for wood and its density is $300 \textrm{ kg/m}^3$. The area of contact is $25.0 \textrm{ cm}^2$, the temperature of the coals is $700 ^\circ\textrm{C}$, and the time in contact is 1.00 s.
2. What temperature increase is produced in the $25.0 \textrm{ cm}^3$ of tissue affected?
3. What effect do you think this will have on the tissue, keeping in mind that a callus is made of dead cells?
1. $40 \textrm{ J}$
2. $2\textrm{C}^\circ$
3. The callus cells are expendable since they're dead cells. The living tissue of the foot can easily sustain a $2\textrm{C}^\circ$ rise in temperature without damage.

# OpenStax College Physics for AP® Courses, Chapter 14, Problem 35 (Problems & Exercises)

In order to watch this solution you need to have a subscription.