A vertical-launch research drone is programmed to reach a target height of 500 metres. The drone’s vertical velocity, w m s−1w\text{ m s}^{-1}w m s−1, is modelled by the equation:
w=25.6−20e−0.5t−0.04e0.25t w = 25.6 - 20e^{-0.5t} - 0.04e^{0.25t} w=25.6−20e−0.5t−0.04e0.25twhere ttt is the time in seconds after the start of the ascent phase.
Find the maximum vertical velocity of the drone, giving your answer to one decimal place. Fully justify that the value you have found is a maximum.
Find an expression for the height of the drone above its starting position, hhh, in terms of ttt.
In a specific test flight, the drone reached the 500-metre target in exactly 28.0 seconds. Comment on the accuracy of the model.
864 exam-style questions on Edexcel A Level Maths Integration, covering 11.1 Integrating Standard Functions, 11.2 Integrating f(ax + b), 11.3 Using Trigonometric Identities, 11.4 Reverse Chain Rule, 11.5 Integration by Substitution, 11.6 Integration by Parts, 11.7 Partial Fractions, 11.8 Finding Areas, 11.9 The Trapezium Rule, 11.10 Solving Differential Equations, and 11.11 Modelling with Differential Equations. Each one has a worked solution and a mark scheme showing where the marks go.