# Homework Help: Calculating An Acceleration To Arrive With Zero Velocity

1. Nov 6, 2009

### eddieparker

Hello!

I'm new to the forums, so apologies if I've put this in the wrong forum. I was debating on placing this in the 'Homework' section, but this is really just a problem I'm having with an application I'm writing, so I wasn't sure if it applied. Anyhow, please file accordingly, and I'll know better for next time.

Anyhow, it's been years since I've used my physics, and I'm quite rusty. I'm working on an application which is trying to return an acceleration for an object that is moving in a frictionless world. At any point in time, I have access to its:

- Velocity
- Position
- Goal

What I'd like to do is have the function return the appropriate deceleration such that it arrives at it's goal with zero velocity.

I'd appreciate anything from pointers to formula's, to discussions regarding possible solutions, etc.

The key thing is that I don't have access to anything save the time since the last calculation, and I'd prefer not to specify the amount of time for the deceleration to occur (that is, I'd prefer the deceleration to scale depending on the velocity).

Cheers!

-e-

2. Nov 6, 2009

### Staff: Mentor

Welcome to the PF. I went ahead and moved the thread -- this is the best place for it.

You will use the kinematic equations of motion, for a constant acceleration (that is the simplest form, and should work for what you want to do).

http://en.wikipedia.org/wiki/Kinematics (scroll down to the Kinematics of Constant Acceleration)

They are equations that relate position, velocity and acceleration. See if that helps, and ask specific questions if you are confused about something. Have fun on the project!