Vectors & Forces: Find Resultant Direction & Magnitude

  • Thread starter Thread starter themadhatter1
  • Start date Start date
  • Tags Tags
    Forces Vectors
Click For Summary
SUMMARY

The discussion focuses on calculating the resultant direction and magnitude of two vectors given an angle of θ=30 degrees. The first vector is defined as <220,0>, while the second vector is calculated using trigonometric functions, resulting in coordinates of <[150√(3)]/2,75>. The user initially computes the resultant vector incorrectly, arriving at a magnitude of 590.63 Newtons, which contradicts the textbook answer of 357.85 Newtons. The error is identified in the calculation of the x-component of the vector sum, which should be corrected to [440+150√(3)]/2.

PREREQUISITES
  • Understanding of vector addition
  • Knowledge of trigonometric functions (sine and cosine)
  • Familiarity with Newtons as a unit of force
  • Ability to manipulate square roots in calculations
NEXT STEPS
  • Review vector addition techniques in physics
  • Learn about trigonometric functions in vector resolution
  • Practice calculating magnitudes and directions of resultant vectors
  • Explore common errors in vector calculations and how to avoid them
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and vector analysis, as well as educators seeking to clarify vector addition concepts.

themadhatter1
Messages
139
Reaction score
0

Homework Statement



If θ=30 degrees find the direction and magnitude of the resultant of these forces.
[PLAIN]http://img194.imageshack.us/img194/7899/image2iw.jpg

Homework Equations





The Attempt at a Solution



Ok, so I know I have to add both of the vectors. I need to find the coordinates to do so. The first vector's coordinates must be <220,0>. Next I need to find the second vector's coordinates:

x=150cos30
x=[150√(3)]/2
y=150cos30
y=75

so the second vector has the coordinates <[150√(3)]/2,75>

If you add the second and the first vectors you get <[590√(3)]/2,75>

Then I found the magnitude of this new vector to be 590.63 Newtons. However, this is wrong because the book's answer section says the magnitude should be 357.85 Newtons.

If i go on to find the direction that also turns out wrong. What am I doing wrong?
 
Last edited by a moderator:
Physics news on Phys.org
The x-component of your vector sum is 590*sqrt(3)/2, which is about 510. That is incorrect, and is too large (you should get about 350). Take a look again at your calculation for this component.
 
Ahh. Thanks, I found my error. The x component should be:

[440+150√(3)]/2
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 12 ·
Replies
12
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
7
Views
2K