# VERY simple question about motion

1. Feb 18, 2006

### Signifier

Okay, this is highschool physics I know but I still need to ask it.

Say I give something a constant acceleration A straight up into the air (A = [0,0,+Az]). If I ignore drag, then the object's z-velocity as a function of time with this constant acceleration will be

(Az - g)t

(where Az is the z-component of the acceleration) if the initial z-velocity at time t = 0 is 0. Am I correct?

Next question: say that an object is travelling straight up through the air with a constant velocity V0. Is the object's z-position as a function of time equal to

V0t - 0.5gt^2 + Z0

(where Z0 is the initial z position) or is it something else?

Sorry if I didn't word these questions right - I'm still very new to this.

2. Feb 18, 2006

### dicerandom

If the object were traveling straight up at a constant velocity you wouldn't have the 0.5gt^2 term, this case would be equivilant to having Az=g in your previous example.

3. Feb 18, 2006