Motion question for science?

Question

it might be easy but im dumb at science

a girl drops her engagement ring out of a 10th storey window. Just as it hits the ground it is travelling at 40ms-1 after falling for 4seconds

Calculate the acceleration due to gravity

please help me with working out shown please

Answer 1

acceleration due to gravity is the same for all objects regardless of the mass of the object or the height from which it falls.

Acceleration due to gravity is a constant.

Acceleration due to gravity = 9.8 m/s/s or 9.8 m/s^2

Answer 2

final velocity, v = 40 m/s

time, t = 4 s

We'll assume that she initially holds and then drops the ring, which means:

initial velocity, u = 0 m/s

acceleration, a = ?

Use this motion equation (you should remember it):

v = u +at

Rearrange the above equation to make 'a' the subject

v - u =at

a = (v-u)/t

So,

a = (40 - 0)/4 = 10 m/s^2