A knight sits on a castle wall during a siege.To while away the time, he notes that boulders catapulted from below land on the top of his wall with a vertical velocity of 9.9 m/s. If he is 35 m above the catapult, what is the initial velocity of the boulders? Theacceleration of gravity is 9.8 m/s

Question

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Answer 1

Use
v1^2-v0^2 = 2aS
v1=final velocity
v0=initial velocity
a=acceleration
S=distance
Use an appropriate frame of reference such as positive = upwards.