Calculate Gravitational Field Strength

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Homework Statement

Given Radius is 4.76*10^5 m
Astronaut drops a hammer of 0.85kg from a height of 1.25m. It takes 3s to reach the ground
What is the gravitational field strength?

Homework Equations

The Attempt at a Solution

g=a=Δv/t
v=d/t
v=1.25/3

a=1.25/3/3

But that's not the answer

 

[PeterO]

Homework Statement

Given Radius is 4.76*10^5 m
Astronaut drops a hammer of 0.85kg from a height of 1.25m. It takes 3s to reach the ground
What is the gravitational field strength?

Homework Equations

The Attempt at a Solution

g=a=Δv/t
v=d/t
v=1.25/3

a=1.25/3/3

But that's not the answer

That 1.25/3 is the average velocity.

Our formulas make use of a specific velocity, usually initial or final depending on which formula you wish to use.