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Internal energy<span> is defined as the </span>energy<span> associated with the random, disordered motion of molecules. It is denoted by U and calculated by the expression:
</span>Δ<span>U = Q - W
We calculate as follows:
</span>ΔU = 68 J - 32 J
ΔU = 36 J
-- The circumference of the track is (2 · π · radius).
Circumference = (2 · π · 1.67m) = 10.49 meters .
-- The train's speed is (31.5 cm) / (10.49 m) of the track's circumference, per second. That's ...
(31.5 cm) · (1m / 100cm) / (10.49 m / circumference) =
(31.5 / 100 · 1,049) (cm · m / cm · m) =
= 0.030 of the circumference per second.
The train performs 0.03 revolution per second.
It takes (1/0.03) = about 33.3 seconds to complete one revolution of the track.