Resultant Force: Something I am messing up on in calculation - ?

[nukeman]

Resultant Force: Something I am messing up on in calculation - ?

Homework Statement

Hey all,

This is a resultant force word problem. I will just post the my answer and the problems answer. I have no idea why there is a different answer here.

Correct: R^2=1500^2+2300^2 - 2 x 1500 x 2300 Cos(138)
Correct Answer = R = 3559.2 Newton

My answer is WAYYY off, so there is something I am missing here...

By the way, I am using the TI-89 Titanium

Thanks for any help!

Homework Equations

The Attempt at a Solution

 

[berkeman]

Homework Statement

Hey all,

This is a resultant force word problem. I will just post the my answer and the problems answer. I have no idea why there is a different answer here.

Correct: R^2=1500^2+2300^2 - 2 x 1500 x 2300 Cos(138)
Correct Answer = R = 3559.2 Newton

My answer is WAYYY off, so there is something I am missing here...

By the way, I am using the TI-89 Titanium

Thanks for any help!

Homework Equations

The Attempt at a Solution

I get the correct answer just typing it into a cheap ativa scientific calculator.

Can you say what keystrokes you used to get your incorrect answer? I did something like:

cos 138 =

* 2300 =

* 1500 =

* -2 =

+ 2300^2 =

+ 1500^2 =

SQRT =

 

[SammyS]

Maybe it's TOO much calculator for too SMALL a problem.

First question: Is you calculator in 'degree' mode, like berkeman's obviously is?

 

[nukeman]

Thanks both of you.

I figured it out. Sammy, you were basically right, it was too much of a calc for it. Yes, I was in the wrong mode. PAIN in the butt!

So, pulled out my dusty Casio calculator and BOOM! solved :)

Thanks guys