Skip to main content
B
BB_1410064610-Marble
10-Marble
October 9, 2025
Solved

Wrong Answers

  • October 9, 2025
  • 3 replies
  • 843 views

I'm using MathCAD 9.0.0.0. I laid our 2 sets of 3 equations. One set is using variables. The other set has the values plugged straight in. The set with the variables should equal the set with the values because the values are the same, but they don't and none of them equal the correct answer.

 

What should happen is...

Rx=Rx=-22

Ry=Ry=211.5

R=r=213

My MathCAD program is written to follow this example...

BB_14100646_0-1759967466251.png

This is how my MathCAD program looks...

BB_14100646_1-1759967540271.png

Ignore the 25 degrees and the 75 degrees in the diagram. This is a homework problem altered to match the example problem so I can test to make sure it works before plugging in the values for the homework problem. Also, I'm interested in fixing the "values" problems Rx, Ry, and r. I only created those to figure out why my variable problems Rx, Ry, and R aren't working. Attached is my program.

 

Thanks,

    Brent

 

Best answer by StuartBruff

StuartBruff_0-1759969108174.png

 

3 replies

B
BB_1410064610-MarbleAuthor
10-Marble
October 9, 2025

Something seems off with MathCAD calculation because even when I plug the "values" in the last equation...

BB_14100646_0-1759968815504.png

...but when running this through Excel, I get...

212.6411

...which round up to the 213 in the hand written example.

 

Thanks,

     Brent

S
StuartBruff23-Emerald V
23-Emerald V
October 9, 2025

Be careful of what you're squaring ...

 

2025 10 09 B.png

    B
    BB_1410064610-MarbleAuthor
    10-Marble
    October 9, 2025

    Thank you. That explains part of it, but I still need to resolve the rest.

    S
    StuartBruff23-Emerald VAnswer
    23-Emerald V
    October 9, 2025

    StuartBruff_0-1759969108174.png

     

      B
      BB_1410064610-MarbleAuthor
      10-Marble
      October 9, 2025

      I thought I tried that yesterday, but it all seems to be working today. Thank you!

      S
      StuartBruff23-Emerald V
      23-Emerald V
      October 9, 2025

      No worries.  Is that all of your problems sorted out?

       

      Stuart

      F
      Fred_Kohlhepp23-Emerald I
      23-Emerald I
      October 9, 2025

      I'm sure you've already been told; "lb" is not force, it's mass.  If you want force you use "lbf".

       

      And you should know that mathcad does vector math, which can make this easy,

      Terms & ConditionsCookie settingsAccessibility statement