Physics help pleaseeee!!!!

An astronaut drops a feather from 2.3 m above the surface of the moon.If the acceleration of gravity on the moon is 1.64 m/s2, how long does it take the feather to reach the surface?

The tallest volcano in the solar system is the 28 km tall Martian volcano, Olympus Mons.An astronaut drops a ball off the rim of the crater and that the free fall acceleration of the ball remains constant throughout the ball’s 28 km fall at a value of 2.5 m/s2. (We assume that the crater is as deep as the volcano is tall,which is not usually the case in nature.)Find the time for the ball to reach the crater floor.Answer in units of s.

Find the magnitude of the velocity with which the ball hits the crater floor.Answer in units of m/s

In free - fall problems, the initial velocity is equal to zero:
a) d = Vit + 1/2at^2
2.3 m = (0) + 1/2(1.64 m/s^2)t^2
t = 1.67 s

b) d = Vit + 1/2at^2
(28 km)(1000 m/1 km) = 0 + 1/2(2.5 m/s^2)t^2
t = 149.7 s

c) Vf = Vi + at
Vf = 0 + (2.5 m/s^2)(149.7 s)
Vf = 374.25 m/s

Let d rep. distance = 2.3m
Let v_1 rep. initial velocity = 0
Let a rep. acceleration = 1.64m/s^2
Let t rep. time = ?

Use the kinematic equations:

d = v_1 x t + (1/2) t^2 x a

v_1 = 0, so
sqrt(2d*a) = t
t = 2.7466

Use a similar strategy for the second question.