1) Suppose you have a street light at a height 10 meters. You drop a rock vertically so that it hits the ground at a distance 5 meters from the street light. The shadow of the rock moves along the ground. Find the speed of the shadow of the rock at the moment that the rock is 3 meters above the ground and moving with the speed of 5 m/s.
2) You say goodbye to your friend at the intersection of two perpendicular roads. At time t = 0 you drive off North at a (constant) speed v and your friend drives West at a (constant) speed w. How fast is the distance between you and your friend increasing at time t?
What should start with these two?