A skier weighing 65 kg (including the mass of skis) descends a slope with a length of 400 m and an incline of 12. The kinetic friction coefficient between the snow and the skis is 0.15. The skis have a mass of 4.8 kg, and the specific heat of the material that makes up the skis is 600 J/(kgK). During the descent, 20% of the work done by friction is transferred to the skis.

a) What is the work done by friction during the descent? A complete solution should include a force diagram. If your memories of mechanics are far on this subject, refer to your book.

b) What is the change in temperature of the skis when the skier reaches the bottom of the slope?

Question 7

The internal energy of a system increases by 4500 J when it absorbs 1500 J of heat and its volume decreases by 0.01 m3. The process occurs at constant pressure. Determine the pressure.