Answer:
0.178 °C
Explanation:
Given:
The frictional force, F = 48 N
Number of rubs, n = 18
Distance covered per rub, d = 7.16 cm = 0.0716 m
Total distance covered in 18 rubs, D = 0.0716 × 18 = 1.288 m
mass of the tissues warmed, m = 0.1 kg
Now,
Work done, W = Force × Displacement
W = 48 × 1.288 = 61.8624 J
Now,
Work done is the change in heat
W = ΔQ = 61.8624 J
also,
ΔQ = mCΔT
where, C is the specific heat
for human tissue, C = 3470 J/kg°C
thus,
61.8624 J = 0.1 × 3470 × ΔT
or
ΔT = 0.178 °C
Hence, the change in temperature is 0.178 °C
