roblem 1: Projectile. A 76kg boulder is rolling horizontally at the top of a vertical cliff that is 20m above the surface of a lake, as shown in figure. The top of the vertical face of the dam is located 100m from the foot of the cliff, with the top of the dam level with the surface of the water of the lake. A level plain is 25m below the top of the 20m Cliff 100m dam. Plain What must be the minimum speed of the rock just as it leaves the cliff so it will travel to the plain without striking the plain? a. b. How far from the foot of the dam hit the plain’?