# Homework Help: Solving for time with these variables

1. Dec 3, 2012

### JazzMasterKC

Ok, I think I'm missing some math knowledge and is to why I can't solve this.. or maybe I'm just burnt out for the day.. However here is the situation:

Mass = 0.06kg
Impact Velocity = 7.34m/s
Final Velocity = 0m/s
Displacement from impact velocity and final = 0.099m
Acceleration = 9.8 m/s/s (gravity)

I need to figure how long it takes in seconds for when the object went from impact velocity to final. Where I'm stuck is where do I through gravity in an equation? I can figure this out without the gravity but for some reason it's tripping me up.

Background: I really like physics, and this is extra apart from the assignment (I'm curious).. I'm in high school physics and also in college algebra.

~ Thanks

2. Dec 3, 2012

### PhanthomJay

This is a good question, but since you have the displacement and velocities given, you can solve for the time using one or more of the kinematic motion equations. There is no need at this point to look at gravity, since its effects on the deceleration during impact have already been incorporated into the given values based on the data. Gravity forces would come in later when you looked at impact forces.

3. Dec 4, 2012

### JazzMasterKC

Ah I see, thanks!