a ball is thrown upward at a speed of 12 m/s. It will reach the top of its path in about:

Question

a) 0.6 sec
b) 1.2 sec
c) 1.8 sec
d) 2.4 sec

Please explain how you find the answer!!! I cannot figure it out

Answer 1

speed at the top is zero.

Vf=vi-9.8t
0=12-9.8t

t= about ...

Answer 2

I learned the formula to be v=gt...why are you subtracting?

Also what is vf and vi?

Answer 3

vf= final velocity, which is zero at the top.
vi is initial velocity.