A drone of mass 5.0kg changes its velocity in two successive stages while flying at constant altitude.
Stage 1: The drone is initially moving due east with a speed of 10ms−1. A steady wind acts for 4s, after which its speed is 10ms−1 directed 30∘ north of east.
Stage 2: Immediately thereafter, the drone’s rotors act for 3s, bringing its velocity to 12ms−1 due north.
a. (i) For the initial, intermediate and final velocities, write the momentum components along the east (x) and north (y) directions.
b. (ii) Calculate the change in momentum during Stage 1 and determine the average force exerted by the wind.
c. (iii) Calculate the change in momentum during Stage 2 and determine the average force exerted by the rotors.
d. (iv) Find the net change in momentum from the start of Stage 1 to the end of Stage 2, giving its magnitude and direction.