# Math Help - Force Vectors problem

1. ## Force Vectors problem

Hello,

Can someone help explain the following problem? It is supposedly a "review" question but I really have no idea where to start. Thanks.

A force vector has a magnitude of 340 newtons (N) and points at an angle of 60.0° below the positive x axis.

(a) What is the algebraic expression for the x scalar component Fx of the force vector? Express your answer in terms of the magnitude F of the force vector and the angle θ that specifies the direction below the positive x axis. Remember that scalar components can be positive or negative, depending on whether they point, respectively, along the positive or negative axis. (Answer using F for F and theta for θ.)

(b) What is the x scalar component Fx of the force vector?

(c) What is the algebraic expression for the y scalar component Fy of the force vector? Express your answer in terms of the magnitude F of the force vector and the angle θ that specifies the direction below the positive x axis. Remember that scalar components can be positive or negative, depending on whether they point, respectively, along the positive or negative axis. (Answer using F for F and theta for θ.)

(d) What is the y scalar component Fy of the force vector?

Any help would be appreciated and I am sure that if someone could explain parts a and b I could do c and d.

Thanks,
juventinoalex

2. Use trigonometry to resolve the magnitude/direction description into cartesian coordinates. Draw a triangle from the origin along the angle. Label sides, and see what the sin and cos of the angle give you.

3. OK, I have the algebraic expression as being 340 sin 60 = 294.45 for the y which I know is correct and 340 cos 60 = 170 for the x compnent which I also know is correct. I think the thing that has me stuck is what to write in for the algebraic expression. Do they just want 340 sin 60 and 340 cos 60?

4. Actually all they wanted was Fcostheta and Fsintheta. Thanks for the help though.

5. They're after

$F_{x}=F\cos(\theta)$ and
$F_{y}=F\sin(\theta).$

You already know these formulas, or you wouldn't be able to compute the components the way you did. Note: the angle is prescribed BELOW the x-axis. So that means the angle isn't 60 degrees. Instead it's what?