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?

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Physics

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2 December, 00:04

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?

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Joel Schaefer · Answer 1

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