## anonymous one year ago What is the average vector acceleration of a car that changes its velocity from 30km/h south to 40km/h east over a time of 5.0s?

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1. johnweldon1993

Hmm, kinda worded weird However..we know $$\Large a = \frac{\Delta v}{t}$$ Since the velocity is changing directions as well...it wont simplify COMPLETELY! but that's okay $\large a = \frac{40i - 30j }{5.0}$ I hope you know that notation: "i" meaning in the x-direction and "j" meaning in the y-direction So that acceleration vector would be $\large \vec{a} = 8i - 6j$

2. johnweldon1993

Which kinda makes sense if you think about it...the motion looks like |dw:1443043644332:dw|

3. johnweldon1993

If we look on a coordinate plane |dw:1443043692012:dw|

4. johnweldon1993

So the resulting vector would be down down (so -j) and going right (so +i)

5. anonymous

shouldn't the j portion be negative and then you get 40--30

6. anonymous

And how would i give a numerical answer with an angle and km/h/s for velocity?