(a)[1]
State the meaning of work done.
(b)[1]
Use your answer in (a) to demonstrate that the SI base units for energy are $\text{kg m}^2\text{s}^{-2}$.
(c)[3]
A metal rod is heated at one end, causing thermal energy to travel to the other end. The thermal energy $E$ that passes through the rod in time $t$ is given by $E = \dfrac{cA(T_1 - T_2)t}{L}$, where $A$ is the cross-sectional area of the rod, $T_1$ and $T_2$ are the temperatures of the ends of the rod, $L$ is the length of the rod, and $c$ is a constant. Determine the SI base units of $c$.