# Homework Help: Acceleration in g units

1. Sep 6, 2006

### physics newb

Question:
An object is moving on land at a speed of 1020 km/h. This object goes from full speed to a complete stop in 1.4 seconds.
In g units, what acceleration did the object 'experience' while stopping?
My guess is I have to plug in -9.8 m/s into this equation, but I'm not sure how.
Any help? I hope this is the right forum. Thanks

2. Sep 6, 2006

### Mattara

1 g = 9.82m/s2

Do you know the formula for acceleration?

3. Sep 6, 2006

### physics newb

Thanks for the quick reply. I don't know the formula for acceleration, at least not off the top of my head.

4. Sep 6, 2006

### HallsofIvy

acceleration is rate of change of speed. The speed went from 1020 km/hr to 0 km/hr, a change of -1020 km/hr in 1.4 seconds.

You will want to change km/hr to m/s.

5. Sep 6, 2006

### physics newb

So it accelerated at -283.3 m/s, now do I divide that by the -9.8 m/s, and that's my answer? I came up with 28.91 g units.

6. Sep 7, 2006

### physics newb

Something just accrued to me. What do I do with the 1.4 seconds? Do I take the 28.91 g units and figure out what the answer would be for 1 second, making it 20.65 g units?

7. Sep 1, 2008

### hvb5031

Yo so is it 28.91 or 20.65..
so what hall are you in...physics 211!!!