Problem: At noon, ship A is 90 km west of ship B. Ship A is sailing south at 40 km/h and ship B is sailing north at 20 km/h. How fast is the distance between the ships changing at 2:00 PM?
Click and drag the slider t to change the time. The rate of change of the distance between the ships at time t is given at right.
Experiment a bit:
• Click and drag the green point x to change the starting distance between ships.
• Click and drag the sliders va and vb to change the velocities of the ships.