Question

A branch falls from a tree. How fast is the branch moving after 0.28 seconds?

Answer 1

This is an issue where we can use the definition of acceleration. That is, the change in velocity per some change in time.
Also, acceleration is gravitational acceleration.
\(a=\dfrac{\Delta v}{\Delta t}\)
And
\(g=a\), right?

So
\(g=\dfrac{\Delta v}{\Delta t}\)

So, we have that the initial velocity is 0 at the start of the fall. So, you can think that the change in velocity is the new velocity. If you want to see the math that agrees,
\(\Delta v=v_f-v_0=v_f-0=v_f\)

Does that help?