4. A shallow narrow river flows along a straight path towards the edge of a cliff. The water flows in a smooth stream all the way to the ground. The speed of the river just before going over the edge is 2.5 m/s. The cliff is 50 m above the ground. Neglect air resistance. a. (5 points) Draw a good physics diagram. b. (5 points) How long does it take the water to hit the ground? you c. (10 points) What angle relative to vertical does the water hit the ground at