# Forces

• Oct 4th 2007, 08:39 PM
cinder
Forces
A man is dragging a trunk up the loading ramp of a mover's truck. The ramp has a slope angle of $\displaystyle 20.0 ^\circ$, and the man pulls upward with a force $\displaystyle \vec{F}$ whose direction makes an angle of $\displaystyle 30.0 ^\circ$ with the ramp.

1. How large a force $\displaystyle \vec{F}$ is necessary for the component $\displaystyle F_x$ parallel to the ramp to be 6$\displaystyle 0.0 {\rm N}$?

2. How large will the component $\displaystyle F_y$ perpendicular to the ramp then be?

I've got the answers: 69.3 N and 34.6 N respectively, but I don't know how to actually work the problem and get those answers.

I think that $\displaystyle \vec{F}$ is the same as $\displaystyle \vec{F_x}$ and $\displaystyle \vec{F_y}$, but I don't know if that helps me or not.
• Oct 4th 2007, 09:26 PM
Spimon
I hope this helps a bit
The angle of the ramp isn't used in this problem because you're already given the force required to move the case up the ramp. That angle would have been used to detemine that force.
Fx and Fy are not the same as F vector. Fvector is the force the moving guy is exerting on the case, Fx is the component parallel to the ramp and Fy is the component perpendicular to the ramp.
Let me know if this is unclear in any way.

Make sure you're VERY familiay SOH-CAH-TOA for these type of questions...

http://img444.imageshack.us/img444/9...cesproblp9.jpg
• Oct 4th 2007, 09:55 PM
cinder
Oh! That helps a lot! Especially for the second question.

It seems I was doing the first question correctly, but I wasn't in "degree" mode, so I was getting a different answer.

Thanks for taking the time to draw that out, it really helped!