# A ball falling from rest is located 45m below its starting point 3.0s later. Assuming that its acceleration is uniform, what is its value?

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I know that the appropriate equation is

∆d = vi∆t + 1/2a∆t^2, but I do not understand why.

I know that the appropriate equation is

∆d = vi∆t + 1/2a∆t^2, but I do not understand why.

##### 1 Answer

Oct 21, 2016

The acceleration is

#### Explanation:

Let the acceleration be

Then we can use the equation

So

Aussuming that the downward direction is positive

So

This is