Problem 74GP

IP A cannon is placed at the bottom of a cliff 61.5 m high. If the cannon is fired straight upward, the cannonball just reaches the top of the cliff, (a) What is the initial speed of the cannonball? (b) Suppose a second cannon is placed at the top of the cliff. This cannon is fired horizontally, giving its cannon bails the same initial speed found in part(a). Show that the range of this cannon is the same as the maximum range of the cannon at the base of the cliff. (Assume the ground at the base of the cliff is level, though the result is valid even if the ground is not level.)

Solution 74GP

Step 1 of 6

First our objective is to determine the initial speed of the cannon ball, which is fired upwards and just reaches the top of the cliff under the given conditions. Next we have to prove that the range of the second cannon projected and travelling at the same speed will be equal to the maximum range of the cannon at the base of the cliff.