Hi, I need some help with a homework problem invovling acceleration

[mindgame]

Homework Statement

What is the acceleration of your car?

Time Velocity[ms]
1 8.8
2 12.82
3 16.25
4 20.46
5 24.22
6 28.09
7 31.77
8 35.24
9 39.32
10 42.37
11 44.61
12 46.63
13 49.01
14 50.53
15 52.1
16 52.32
17 53.6
18 53.44
19 53.74
20 53.25

http://img87.imageshack.us/img87/8674/velocitygraphob6.jpg

Homework Equations

The Attempt at a Solution

 

[mindgame]

I really just don't know where to start, is there an equation I need to use or is this much more complicated?

 

[Kurdt]

The definition of acceleration is the rate of change of velocity with time. What you need to do is find out how much the speed changed and in what time, then:

$$a= \frac{\Delta v}{t}$$

 

[mindgame]

(53.25 - 8.8) = 44.45

a = (44.45) / 20s

a = 2.2225 m/s

Is this right?

 

[radou]

What's with the function in the upper right edge v(t) = 3.6688 t + 5.6189 ?

 

[mindgame]

That's just the slope of the trendline for the increasing part of the graph. He told us in class we had to show it.

 

[cristo]

Ok, so from above $$a= \frac{\Delta v}{t}$$ , or to put it another way, a is the gradient of the graph of v against t. Given your trendline, in the form y=mx+c, how can you read off the gradient?