A knight sits on a castle wall during a siege. To while away

Last updated: 7/30/2022

A knight sits on a castle wall during a siege. To while away the time, he notes that boul- ders catapulted from below land on the top of his wall with a vertical velocity of 5.4 m/s. If he is 30 m above the catapult, what is the initial velocity of the boulders? The acceleration of gravity is 9.8 m/s². Answer in units of m/s.