Direction of displacement vector

Click For Summary
SUMMARY

The discussion revolves around calculating the direction of a displacement vector after a boy runs 11.3 blocks North, 5.6 blocks Northeast, and 4.7 blocks West, resulting in a displacement magnitude of 15.2598 blocks. The user initially miscalculated the angle of the displacement vector, incorrectly stating it as 90 degrees. The correct approach involves using trigonometric relationships to determine the angle based on the resultant vector's x and y components, which requires precise vector addition and scaling.

PREREQUISITES
  • Understanding of vector addition and components
  • Knowledge of trigonometric functions, specifically sine and cosine
  • Familiarity with coordinate systems and angular measurements
  • Ability to calculate magnitudes using the Pythagorean theorem
NEXT STEPS
  • Learn vector addition techniques in physics
  • Study trigonometric relationships for angle determination
  • Explore the concept of resultant vectors in two-dimensional motion
  • Practice problems involving displacement vectors and their directions
USEFUL FOR

Students in physics, educators teaching vector analysis, and anyone interested in mastering displacement vector calculations and trigonometry.

dlthompson81
Messages
44
Reaction score
0
I got this problem that states:

A boy runs 11.3 blocks North, 5.6 blocks Northeast, and 4.7 blocks West. Determine the length of the displacement vector that goes from the starting point to his final position.

I got the answer to this part. It was 15.25979798 blocks.

Here is the next part:

Determine the direction of the displacement vector. Use counterclockwise as the positive angular direction, between the limits of -180 degrees and +180 degrees measured from the East. Answer in units of degrees.

Now when I drew this out I got a diagram with the first vector going north at 90 degrees, the second vector goes northeast at 45 degrees, and the third vector goes back west at 45 degrees which is back parallel to the x-axis. From the looks of my diagram the head of the final vector stops when it gets to the point where the first vector would have intersected it had it kept going. I entered 90 degrees, but it told me that was wrong. Where did I go wrong? Thanks for the help.
 
Physics news on Phys.org
Do it right. Add the three vectors as vectors and then find the magnitude of the resultant.
 
You probably didn't draw it to exact scale. I assume you solved for the magnitude of the displacemnt by using sq rt of sum of squares? The angle is determined using what trigonmetric relationship between the y and x components of the resultant displacement? (Please round off your answers to not more than 1 decimal point).
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 19 ·
Replies
19
Views
8K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
Replies
4
Views
1K
  • · Replies 5 ·
Replies
5
Views
4K
Replies
3
Views
2K
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K