the initial velocity of the object is 3 m/s
vi = -3 m/s
here negative sign is showing direction, it means the object is thrown vertically upwards,
when it touches the ground its velocity will be the same as initial velocity.
so,
v f = 3 m/s
the acceleration of the object was the acceleration due to the gravity.
so,
a = 9. 8 m/s^2
and the displace ment is zero. because it was thrown vertically upwards, so no horizontal displacent will be there.
y = 0m
