7. What is an unbalanced force? a) Forces that are equal in size but the same in direction
b) Forces that are unequal in size but same in direction
c) Forces that are equal in size but opposite in direction
d) Forces that are unequal in size but opposite in direction

If a simple machine reduces the strength of a force, what must be increased?

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.

Which accounts for an increase in the temperature of a gas that is kept a constant volume