Earth is being added to a pile so that, when the height of the pile is \(h\) metres, its volume is \(V\) cubic metres, where
$$V = (h^6 + 16)^{\frac{1}{2}} - 4.$$
- Find the value of \(\frac{dV}{dh}\) when \(h = 2\). [3]
- The volume of the pile is increasing at a constant rate of 8 cubic metres per hour. Find the rate, in metres per hour, at which the height of the pile is increasing at the instant when \(h = 2\). Give your answer correct to 2 significant figures. [3]