Using Impulse-Momentum to Find Time of Falling Object

[jheld]

Homework Statement

Use the impulse-momentum theorem to find how long a falling object takes to increase its speed from 5.50 to 9.00 .

Homework Equations

deltaP = impulse
P = momentum (m*v)
impulse = J (integral from ti to tf)

The Attempt at a Solution

3.5 seconds, though, I knew before that it was incorrect.

 

[jheld]

well, I got it, now :)
vf = vi + at
-9 = -5.5 -9.8t
solve for t = .357 seconds