Quick error propagation problem

[mjolnir80]

Homework Statement

we are trying to find the x -component of a velocity vector (V*cos\theta)
our uncertainty for the velocity is +-.0003 and for the and it is .5(in degrees)
how do we propagate the error for this
v=.048 while \theta =27 degrees

Homework Equations

The Attempt at a Solution

using partial derivatives :
(vSin\theta).5 (degrees)+ (cos\theta).0003=
(0.048*sin27)0.5+(cos27).0003=0.02
the problem is this is a really big uncertainti compared to the answer and i was just wondering whether i did this right?

 

[gabbagabbahey]

The method looks fine except that you need to convert your error to radians, as the relation \frac{d}{d \theta} \cos \theta=- \sin \theta is only true when \theta is in radians.

 

[mjolnir80]

thanks allot!