1. Answer the following true or false. Explain.
(a) As a spring is compressed adiabatically, its internal
energy increases.
(b) Energy transfers by heat are induced only as a result
of a temperature difference between a system and its
surroundings.
(c) The total energy of a closed system can change as a
result of energy transfer across the system boundary by heat
and work and energy transfer accompanying mass flow
across the boundary.
(d) The change in kinetic energy, in Btu, of a 10-lb mass
whose velocity decreases from 100 ft/s to 50 ft/s is 1.5 Btu.
(e) In this book, heat transfer to a closed system and work
done on a closed system are each considered positive:
Q > 0 and W > 0, respectively.
Solution
a) true
because of atomoc spin and interatomic vibration, internal energy of spring increases when it
compressed
b) False
latent heat occurs at constant temperature, also pressure difference like compression and pressure
results in heat
c) False
Because in open system mass is not allowed, energy transfer may occur interms of heat and work
d) fALSE
it is 3.16 btu
e) True