An industrial chemical reactor vessel with a circular cross-section and a maximum depth of 30 cm is initially empty. A cooling reagent is pumped into the reactor such that its depth at time ttt seconds is hhh cm.
The volume of reagent in the reactor, V cm3V \text{ cm}^3V cm3, is modelled by the formula:
V=112h2(2h+45)0≤h≤30 V = \frac{1}{12}h^2(2h + 45) \quad 0 \le h \le 30 V=121h2(2h+45)0≤h≤30The reagent is delivered at a constant rate of 225 cm3 s−1225 \text{ cm}^3\text{ s}^{-1}225 cm3 s−1. According to this model:
Determine the time required to fill the reactor vessel completely.
Calculate the rate of change of the depth of the reagent, in cm s−1\text{cm s}^{-1}cm s−1, at the instant the depth reaches 15 cm.
717 exam-style questions on Edexcel A Level Maths Differentiation, covering 9.1 Differentiating sin x and cos x, 9.2 Differentiating exponentials and logarithms, 9.3 The Chain Rule, 9.4 The Product Rule, 9.5 The Quotient Rule, 9.6 Differentiating Trigonometric Functions, 9.7 Parametric Differentiation, 9.8 Implicit Differentiation, 9.9 Using Second Derivatives, and 9.10 Rates of Change. Each one has a worked solution and a mark scheme showing where the marks go.