2, Heat and Molecular Physics 63jug the piston into the cylinder for the soap
bubble to reduce its size by half.
2,25. Why is clay used instead of cement
(which has a higher strength) in laying
bricks for a fireplace? (Hint. Red-clay bricks
are used for building fireplaces.)2.26. A thermally insulated vessel contains
two liquids with initial temperatures T^1
and T2 and specific heats c^1 and c^2 , separat-
ed by a nonconducting partition. The par-
tition is removed, and the difference be-
tween the initial temperature of one of the
liquids and the temperature T established
in the vessel turns out to be equal to half
the difference between the initial tempera-tires of the liquids.
Determine the ratio m 1 /m 2 of the masses
of the liquids.
2.27. Water at 20 °C is poured into a test
tube whose bottom is immersed in a large
amount of water at 80 °C. As a result, the
water in the test tube is heated to 80 °C
during a time t 1. Then water at 80 °C is
poured into the test tube whose bottom is
immersed in a large amount of water at20 °C. The water in the test tube is cooled to
20 °C during a time t 2.
What time is longer: t 1 or t 2?2.28. The same mass of water is poured into
two identical light metal vessels. A heavy
ball (whose mass is equal to the mass of wa-
ter and whose density is much higher than
that of water) is immersed on a thin non-
conducting thread in one of the vessels so
that it is at the centre of the volume of the