You are Here: Home >< Maths

# Mechanic 1 - Minor Resultant Force Problem Watch

1. Here is the question:

Find the magnitude of the resultant and the angle the resultant makes with the positive x-axis for the following forces.

(Image)

I know how to get the resultant force.. 6.7
It's just the angle the puts me off. I get 26.6.
But on the answer book they have 206.6.

They added 180 on. It's the "Find the angle with the positive X-axis that confuses me"

Any ideas??
2. You're finding the angle with the negative x axis (which is pointing in the same direction as the 6 force). However they want the angle with the positive x axis which points in the other direction.
3. (Original post by ttoby)
You're finding the angle with the negative x axis (which is pointing in the same direction as the 6 force). However they want the angle with the positive x axis which points in the other direction.

How did they get 206.6 then?
4. (Original post by CtrlAltDefeat)

How did they get 206.6 then?
It's wrong. 206.6 would be the angle, clockwise, from the positive y.
5. (Original post by CtrlAltDefeat)

How did they get 206.6 then?
Sorry I tried to reply earlier but then the website hanged and I forgot about it. 206.6 is correct.

Imagine you're pointing in the positive x direction (to the right). Then turn anticlockwise 180 degrees to point in the negative x direction. Then turn another 26.6 degrees anticlockwise until you're pointing in the direction of the resultant force. So the force is 180+26.6=206.6 degrees anticlockwise from the positive x axis.
6. hi,
i had the same problem, with the same question.

the positive x-axis is where zero degrees begins and you have to go round anticlockwise to complete the full 360 degrees turn.

the question is asking about the angle the resultant makes with the positive x-axis.

therefore, alone, the angle of the resultant force is 26.5 or something. but with the positive x-axis, you have to add on 180, in order to reach the resultant force form the positive x-axis.

which means that the angle made with the positive x-axis is 206.

try drawing it and dot the positive x-axis and then trace the angle it from that axis all the way till the angle of the resultant force. thats what its asking you to find.

im sorry, im not good at explaining things well, but i thought id try because it took me a lot of time to get my head around this too.

good luck!

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: December 7, 2010
Today on TSR

### Oxford grad sues for £1m

Claims damages because he didn't get a first

### 'No evidence of shots fired' at Oxford Circus

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.