http://i42.tinypic.com/2hq8093.jpg

its 7a and 8a that im stuck on

thnkz

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- May 11th 2009, 08:50 AMKakaduQuick Easy Vectors Question
http://i42.tinypic.com/2hq8093.jpg

its 7a and 8a that im stuck on

thnkz - May 11th 2009, 09:29 AMe^(i*pi)
7a) If you draw a diagram with i on the x axis and j on the y axis then you can use the tan to find the argument.

In your case it is

. Since this is taken from the horizontal the vertical (bearing) will be 90 minus your answer:

The speed component is given already

8a) If two vectors are parallel then**b**= k**a**where b and a are vectors and k is a constant:

Equate the j component:

Equate the i component: to get a = 0.5 - May 11th 2009, 01:48 PMKakadu
on 7a it says find the vector how come your answers a degree

and in the back of the book it says (72i + 96j) - May 12th 2009, 10:26 AMearboth
- May 21st 2009, 06:28 AMKakadu
- May 21st 2009, 10:35 AMearboth
If you want to transform the vector into a unit vector you have to multiply the vector by .

If then

The vector has the same direction as (3, 4) but a length of 1.

If you multiply this vector by 120 km/h you'll get a vector with a length of 120 and the direction of (3, 4) - May 21st 2009, 11:08 AMKakadu
thankz

can you do question 7c and 9 for me please - May 21st 2009, 09:19 PMearboth
I'm going to do #9.

(To help you more efficiently you should show some work of your own so we can see where you need some additional assistance)

Two vectors are parallel if .

#9a)

At t = 12 you'll get the position vector (144, 0) which is parallel to (1, 0)

#9b)

By substitution you'll get:

t = -4 will yield the vector (16, -16) which is parallel to the vector (1, 1) but pointing into the opposite direction.

t = 3 will yield the vector (9, 9) which is parallel to (1, 1).