Calculating Net Force with Multiple Forces Acting on an Object

[homevolend]

Homework Statement

3 people are pulling on a money bag. Person 1 pulls 35N [E]. Person 2 42N [N]. Person 3 53N [W]. What is fnet on money bag?

Homework Equations

The Attempt at a Solution

I drew it like this.


[PLAIN]http://img684.imageshack.us/img684/3453/draww.png

So I got the 18N by doing 53-35 for the top line which is moving in the west direction.


So to find the Fnet I did x= 42² + 18²

So Then I got x = 1764 + 324

x=2088

then square root it I got 45.7 N... I am wondering if this is the correct Fnet or I did it wrong?

Also wondering if I need to also put the theta by doing...


tan-1 18/42 then its 23.2 degrees then I don't know the direction like N of e or s of w. Not sure if I need the theta though or just the fnet in Newtons.





thanks!

 

[PhanthomJay]

Homework Statement

3 people are pulling on a money bag. Person 1 pulls 35N [E]. Person 2 42N [N]. Person 3 53N [W]. What is fnet on money bag?

Homework Equations

The Attempt at a Solution

I drew it like this.


[PLAIN]http://img684.imageshack.us/img684/3453/draww.png

So I got the 18N by doing 53-35 for the top line which is moving in the west direction.


So to find the Fnet I did x= 42² + 18²

So Then I got x = 1764 + 324

x=2088

then square root it I got 45.7 N... I am wondering if this is the correct Fnet or I did it wrong?

Also wondering if I need to also put the theta by doing...


tan-1 18/42 then its 23.2 degrees then I don't know the direction like N of e or s of w. Not sure if I need the theta though or just the fnet in Newtons.





thanks!

Your magnitude of the net force is correct, well done. But since force is a vector, it must have direction also, as your diasgram shows, and you must indicate this direction in order to fully describe the net force. Your angle of 23.2 degrees west of north is also correct. It is usually written as [N] 23.2 degrees [W]. I prefer to just spell it out.

 

[homevolend]

Thanks phantom, appreciate it.