# Homework Help: Force vector - Value and uncertainty for components

1. Feb 17, 2010

### mybrohshi5

1. The problem statement, all variables and given/known data

A force in polar coordinates is given by F1 = 50±2 N at the angle 30±2 degrees.

Find the value and uncertainty for Fx and Fy

Since force is a vector, there will be an error in both its magnitude and direction....

angle calculations must be in RADIANS....

$30\frac{+}{}2 degrees = \frac{\pi}{6} \frac{+}{} \frac{\pi}{90}$

2. Relevant equations

Fx = F cos(θ)
Fy = F sin(θ)

3. The attempt at a solution

Fx is a function of both F and θ so i took the derivative of Fx = F cos(θ) using the chain rule.

$F_{x-error} = cos(\theta)\frac{dF_x}{dF} - F(sin(\theta))\frac{dF_x}{d\theta}$

I did the same for Fy

$F_{y-error}= sin(\theta)\frac{dF_y}{dF} + F(cos(\theta))\frac{dF_y}{d\theta}$

Can i please get some help with what to do next. I am a little lost and confused :(

Thanks for any help :)

Last edited: Feb 17, 2010
2. Feb 18, 2010

### mybrohshi5

Can anyone suggest anything for this?

I know it deals with partial derivatives and everything, im just not exactly sure about all that stuff and what to do for this question and my professor sure as heck doesnt explain it at all :(