http://i42.tinypic.com/2hq8093.jpg
its 7a and 8a that im stuck on
thnkz
http://i42.tinypic.com/2hq8093.jpg
its 7a and 8a that im stuck on
thnkz
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 = ka where b and a are vectors and k is a constant:
Equate the j component:
Equate the i component: to get a = 0.5
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).