Question

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 25 rubs a distance of 7.50 cm each and with a frictional force averaging 51.3 N, what is the temperature increase? The mass of tissue warmed is only 0.100 kg, mostly in the palms and fingers. The specific heat of the tissue is 3500 J/(kg · °C).

Answer 1

Q = mc AT → AT - mc Q: W= Fid = 51.3 x 7 50x10° :. Q = 3.85 J But total. Do of rubs : 25 .: Q = 25 x 3.85 = 96.2 ___m : 0.100 kg_ 3500 JHkqoc J. L : AT 96.2 0.100 x 3500 I: AI = . 27 5 °C