Question

vector is 30 units length and points along positive x axis , vector is 40 units in length and points along a direction 150 from the positive x axis. what is the magnitude of the resultant when the vectors are added ?

Answer 1

Do you know how to decompose vectors using sines and cosines?

Answer 2

yes

Answer 3

can i use c square= a square + b square - 2 a b cos 150

Answer 4

yes,,use the cosine law

Answer 5

You could as long as you are careful about how you draw the triangle.

Answer 6

I think using vector components involves slightly fewer operations though.

Answer 7

what do you mean by fewer operation

Answer 8

Is there any angle between two vector ??

Answer 9

yes the angle is 150 from positive x axis

Answer 10

"what do you mean by fewer operation"
- Depends on how you choose to set it up and solve it. It is possible, as long as you're careful, to punch it out with law of cosines in one step, but there is a chance for error. Decomposing the vectors allows you to be more careful and each of the steps is quite easy.

Both are equivalent, so it shouldn't matter. (would be a good idea to use the other method to check the first)

Answer 11

Can you write this then