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 12 rubs, at a distance of 7.50 cm per rub, and with a frictional force of 45.0 N, what is the temperature increase in degrees Celsius?

Answer 1

Answer:

Explanation:

Total heat = Work done = Force × distance

distance = 0.075 × 12 = 0.9 m

W = 45 × 0.9 = 40.5 joules

Specific heat of the human hand = 3.5 kj/kg = 3.5 j/g

Q = MCΔT

ΔT = (Q) ÷ (MC)

ΔT = 40.5 ÷ (3.5 × 1) = 11.57°C