# Homework Help: Accelration help

1. Sep 13, 2006

### NIZBIT

Just a couple of questions I'm banging my head on. Any help would be great!!

1. Does your accelration have to be negative when you are slowing down?

If I started in a negative direction back towards my initial frame of reference,
accleration would be positive? But isn't that still speeding up?

2. It is a velocity time graph. I'll explain the best I can. It wants to know which is accelrating faster. It is showing 2 graphs. Graph A is a positive velocity with a positive accleration and it has a small slope so all of this is slowly happening. Graph B is positive velocity with a negative accelration and the slope is larger so it is quickly happening.

So when they ask this does it matter if its acclerating or deaccelerating?

2. Sep 13, 2006

### Kurdt

Staff Emeritus
1. Think of acceleration as a vector. Does a vector have to be negative?

2. Acceleration is the rate of change of speed with respect to time so when it asks which is accelerating faster do you think it should matter if it is accelerating or decellerating?

3. Sep 13, 2006

### NIZBIT

So I could have a negative velocity with a positive accelration hence slowing down?

4. Sep 13, 2006

### Kurdt

Staff Emeritus
I think you've hit the nail on the head.