Minimizing a vector in a triangle

  • Thread starter Thread starter Shaybay92
  • Start date Start date
  • Tags Tags
    Triangle Vector
AI Thread Summary
To determine the forces F1 and F2 for towing a truck with a resultant force of 950N along the positive x-axis, F1 is set at 20 degrees from the x-axis. The discussion centers on minimizing the angle of rope two, with one participant suggesting -90 degrees for minimal work, while the textbook indicates -70 degrees. A vector triangle approach is recommended to visualize the problem, emphasizing the relationship between the known sides and the shortest possible third side. The need for a diagram is highlighted, as it is crucial for solving the geometry involved. Understanding the angles and forces is essential for accurately calculating the required towing forces.
Shaybay92
Messages
122
Reaction score
0

Homework Statement



A truck is to be towed using two ropes. If the resultant force is to be 950N, directed along the positive x axis, determine the magnitudes of forces F1 and F2 acting on each rope and the angle at which rope two pulls to ensure that the magnitude of F2 is a minimum. F1 acts at 20 degrees from the x axis.

The Attempt at a Solution



I assumed that to minimize the work required by rope two, it would be -90degrees angle (so it is only required to pull the truck back in line). However, the book says -70degrees?
 
Physics news on Phys.org
Hi Shaybay92! :smile:

(have a degree: º :wink:)
Shaybay92 said:
I assumed that to minimize the work required by rope two, it would be -90degrees angle (so it is only required to pull the truck back in line). However, the book says -70degrees?

Sorry, no idea what you mean. :confused:

Anyway, just draw a vector triangle …

you know the direction and length of one side, and you know the direction of the second side …

what is the shortest the third side can be? :smile:
 
I'm assuming based on the wording that there's a diagram that goes with this? It's kinda hard to solve a geometry problem if there's supposed to be a picture with it.
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Essentially I just have this problem that I'm stuck on, on a sheet about complex numbers: Show that, for ##|r|<1,## $$1+r\cos(x)+r^2\cos(2x)+r^3\cos(3x)...=\frac{1-r\cos(x)}{1-2r\cos(x)+r^2}$$ My first thought was to express it as a geometric series, where the real part of the sum of the series would be the series you see above: $$1+re^{ix}+r^2e^{2ix}+r^3e^{3ix}...$$ The sum of this series is just: $$\frac{(re^{ix})^n-1}{re^{ix} - 1}$$ I'm having some trouble trying to figure out what to...
Back
Top