Question

Two vectors are given by a = 1.8 x - 9.6 y and b = -17.5 x + 1.6 y. What is the magnitude of a?

What is the angle between vector b and the positive x-axis?

What is the magnitude of the vector a + b?

Answer 1

The magnitude of a vector
V=p<b>i</b>+q<b>j</b>
is √(p²+q²).
The angle is given by
arcTan2(q/p) from the <b>i</b> axis if p≠0, or 90 or 270° if p=0 and q>0 or q<0.

Answer 2

sorry but i still don't understand can elaborate on your answer.

Answer 3

consider any vector f= Ax + By

where x,y are coordinates, 90 degrees separated.

The magnitude of f is given by sqrt(A^2+B^2)
so do that above.

Answer 4

thanks for the help
i got the answers for a&c but i cant get b
can you explain further

Answer 5

b = -17.5 x + 1.6 y
the end point of the vector is in the second quadrant (x<0, y>0)
y=1.6
x=-17.5
angle with the x-axis is
tan^-11.6/-17.5=(180-5.2)° (second quadrant)

Answer 6

thanks
i did 360-5.2 instead

Answer 7

360-5.2 would lie in the fourth quadrant, and applies when x=17.5 and y=-1.6, which is not the present case.

Answer 8

i tried 180-5.2=174.8
but it was incorrect

Answer 9

Was 354.8 correct?
Did you check the number of decimals requested?
Is it supposed to be in degrees or radians?

Answer 10

the answer is in degrees and i tried 354.78 it was also wrong and the website didn't comment on the number of decimals

Answer 11

It should definitely not be in the fourth quadrant. You may want to try different decimals, like 180-5.22° or 180-5°.

I usually give less significant digits than required so that it will give you a chance to repeat the calculation with more precision. So my answer usually serves as a check.

Also, check if the vector B is indeed (-17.5 x + 1.6 y)

Answer 12

the units were the problem you had to put deg...
sorry for wasting your time