Finding Magnitude and Angle of Vectors A & B

AI Thread Summary
To find the magnitude of the sum of vectors A and B with magnitudes of 16 and 12 units at an angle of 120 degrees, the cosine rule can be applied. The formula used is |A + B| = √(A² + B² + 2AB cos(θ)), resulting in a magnitude of approximately 12.73 units. For the second part, to find the angle between the vectors given that the difference A - B has a magnitude of 16 units, the sine rule or vector subtraction can be utilized. The discussion emphasizes the importance of understanding vector operations and encourages users to show their work for better assistance. Clarifying the application of relevant equations is crucial for solving these vector problems.
magellaniic
Messages
4
Reaction score
0
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!
 
Physics news on Phys.org


magellaniic said:
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.
 


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 :(
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Finding the magnitude (length) and direction (angle) of a vector
Replies
2
Views
1K
Torque on a Circular Current Loop under a Misaligned Magnetic Field
Replies
1
Views
939
Vector Subtract Given Magnitude
Replies
6
Views
2K
Finding Vector Angle using cosine law
Replies
13
Views
2K
Vectors along different coordinate axes
Replies
2
Views
1K
Vector Addition Question: find angle (A+B & A-B)
Replies
3
Views
1K
Vector cross product anti-commutative property
Replies
9
Views
2K
Finding Vector C: Magnitude and Angle Calculation
Replies
5
Views
4K
Writing a vector parallel and normal to a unit vector ##\hat n##
Replies
26
Views
1K
Resultant of two vectors of equal magnitude
Replies
3
Views
6K

Hot Threads

Recent Insights

Back
Top