# Average velocity

1. Jan 11, 2009

### Draggu

1. The problem statement, all variables and given/known data

A construction worker drops a bolt while working on a high-rise building 320m above the ground. After t seconds, the bolt has fallen a distance of s metres, where s(t) = 320-5t^2, 0 <= t <=8

Find the average velocity for the interval 3<=y<=8

2. Relevant equations

3. The attempt at a solution

I used the formulas $$\Delta$$s / $$\Delta$$t
which then =
s(8) - s(3) / (8-3)

~
~
=55

Is this right?

2. Jan 11, 2009

### snipez90

The magnitude is correct but I think you want to keep the negative sign to indicate direction.