Sum and difference of two vectors with given magnitudes

[magellaniic]

Two vectors A and B have magnitudes A=16 and B=12 units respectively.

A. Find the magnitude of the sum A+B if the angle between the two vectors is 120 degrees.

B. find the angle between the two vectors if the difference A-B has magnitude of 16 units.

Could someone please do a step by step for these two questions? at least the first one.

Thanks very very much!

 

[Ignea_unda]

Two vectors A and B have magnitudes A=16 and B=12 units respectively.

A. Find the magnitude of the sum A+B if the angle between the two vectors is 120 degrees.

B. find the angle between the two vectors if the difference A-B has magnitude of 16 units.

Could someone please do a step by step for these two questions? at least the first one.

Thanks very very much!

As this is in the homework section, I assume that this is class work. As such, we are more than willing to help, but will not do the work for you.

What equations do you think apply here?

Can you show us your work up to the point that you get stuck? That will let us know how to help you best.

 

[magellaniic]

It's not actually a homework problem.

I honestly have no idea how to do the problem.

First thing i though of was to draw a triangle with an angle of 120 degrees. Tried to use Pythagorean theorem but then realized it wasn't a right triangle.

so i really have no clue :(