## anonymous 4 years ago They want you to find the average velocity of a car that goes 160 miles north and 120 miles east. they do D = $\sqrt{(160^2 + 120^2 }$ = 200 miles. Then they do tan^-1 120/160 = 36.87, then 90 - 36.87 = 53.13. WHY do they choose the "90"? because they have chosen different numbers in different problems...

1. amistre64

velocity is a scalar, not a vector; so directions mean nothing

2. amistre64

spose we have an interval from [a,b] such that we know the speed at a; f(a). and we know the speed at b; f(b) the average velocity is then just: f(b)-f(a) ------- b-a

3. amistre64

the 90 here would refer to the right angle formed by turning; the other part is the angle of the tangent of the 2 distances; but i got no idea how that relates to avg. velocity ...

4. anonymous

but in other similar problems, they use numbers like 180, and sometimes that add instead of subtracting...