# Physics Forces Question

• Jan 24th 2009, 04:38 PM
s3a
Physics Forces Question
"Two children playing on the beach are pulling on inner tube. one exerts a force of 45N[N]. The other exerts a force of 60 N[SW]. Wat is the net force acting on the tube?"

Please explain this to me by showing me the math and the visual diagram(s) please.
Thanks!
• Jan 24th 2009, 07:41 PM
Last_Singularity
Quote:

Originally Posted by s3a
"Two children playing on the beach are pulling on ainner tube. one exerts a force of 45N[N]. The other exerts a force of 60 N[SW]. Wat is the net force acting on the tube?"

Please explain this to me by showing me the math and the visual diagram(s) please.
Thanks!

Draw a free body diagram and split up the forces into their vertical and horizontal components.

The first child exerts a force of $45$ in the positive-Y direction.

For the second child, we can split up his force into negative-X and negative-Y components. Specifically, the X component is: $60 cos(45)$ and the Y component is: $60sin(45)$

Adding up the forces, we get:
$F_X = -60cos(45)$
$F_Y = 45 -60cos(45)$

So your resulting force vector, $\hat{F}$, is written as:
$\hat{F} = ( -60cos(45), 45 -60cos(45))$
• Jan 25th 2009, 11:29 AM
s3a
I haven't learnt vectors in math yet, but I am learning it in physics so you've confused me a lot :(. Not only do I not know how to determine its direction but I am confused as to what kind of triangle I am supposed to work with. If it's constructed for me, it'll be easy but unfortunately that is not the case so please help me!