# Calculate the net force acting on the object

1. Sep 23, 2016

### roguekiller93

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

Calculate the net force acting on each object indicated in the following diagrams.
(diagrams attached) I am working on "B"

2. Relevant equations

Sine Law: sin a/a = sin b/b = sin c/ c
Cosine Law: c^2 = a^2 + b^2 -2ab*cos(c)
3. The attempt at a solution
C2 = (2W)2 + (17N)2 – 2(2)(17)Cos 45o

= 4 + 289 – 48.08326112

= 16 N
SinB/ 17 N = Sin 45 / 16 W

= 49o
∴ Net Force is 16 N (W49o N)
I am really struggling with this component of physics.I understand I got the wrong answer for the sine law because I rounded off too early in my cosine law calculations. However I am really struggling to understand how I got the wrong answer for the direction of my resultant vector. It is supposed to be 16 N [W 40 N].

Last edited by a moderator: May 8, 2017
2. Sep 23, 2016

### billy_joule

I can't see any attachment.

3. Sep 23, 2016

### roguekiller93

Sorry. I attached the diagrams now

4. Sep 23, 2016

### Staff: Mentor

It seems that if you componentized the vectors then added the components and then converted the resultant vector back to angle and magnitude.

5. Sep 23, 2016

### roguekiller93

Yes. That's the method they want us to use.

6. Sep 23, 2016

### Staff: Mentor

So show us the i, j components of the vectors then show the components of the resultant one.