Question

1. Consider a sky diver in free fall (a) Draw a free body diagram showing the forces acting on the sky diver. Note that the drag force will be proprtional to velocity squared, and act in the opposite direction to velocity. (b) Apply Newton's 2nd Law to model the skydiver's velocity with a 1st order ODE, treating down as the positive direction. Present your ODE in standard form (c) A skydiver has a mass of 90 kg, and a drag constant of 0.3 kg/m Solve the terminal velocity of the skydiver. Hint: You do not need to solve the ODE in order to find the terminal velocity. (d) Comment on what would change in the ODE model once the parachute has been released. 2. Consider the RL circuit shown below in Figure 1. The resulting ODE for the current was modelled in class. Model an ODE such that the dependent variable is the voltage across the resistor. Present your ODE in standard form VR Fig. 1. RL Circuit

Answer 1