Question

a cannon fires at a castle. the walls are 9m high. if the cannon is pointed at an angle of 60 degrees and has a muzzle velocity of 35m/s will the cannon balls go over the wall or hit the wall?

Answer 1

You need to specify how far the cannon is from the wall. The answer will depend upon it.

There is a vertical velocity component of
Vyo = 35 sin 60 = 25.98 m/s.
The cannonball can rise to a height

H = (V sin 60)^2/(2g) = 34.4 m

Surely the cannonball will clear the wall if the cannon is neither too close nor too far away.