A ball is thrown straight up and reaches a

maximum height of 7.16 m. What was its initial speed? The acceleration
of gravity is 9.8 m/s
Answer in units of m/s.

1 answer

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.