You are Here: Home

# M1 Combining forces

Announcements Posted on
Fancy a fiver? Fill in our quick survey and we’ll send you a £5 Amazon voucher 03-05-2016
Talking about ISA/EMPA specifics is against our guidelines - read more here 28-04-2016
1. Each of two forces has magnitude X N, and the resultant of these two forces has magnitude 12 N. When the magnitude of one of the forces is increased by 70%, the magnitude of the resultant of the two forces becomes 21N. Find X and the angle between the two forces.

I really have no idea what to do here. Completely stuck. Help appreciated.
2. Diagram would be useful.

Apply the cosine rule in each case to get two simultaneous equations.
3. (Original post by ghostwalker)
Diagram would be useful.

Apply the cosine rule in each case to get two simultaneous equations.
Thanks! I drew a few diagrams but didn't think to use the cosine rule.

In an exam, would it matter whether I chose to answer a question by constructing a force diagram or by splitting and combining components (if the question doesn't explicitly state which method to use)?

Or is this something which would depend on the board?
4. (Original post by Julii92)
In an exam, would it matter whether I chose to answer a question by constructing a force diagram or by splitting and combining components (if the question doesn't explicitly state which method to use)?

Or is this something which would depend on the board?
Years since I did A-levels, so can't give a definitive answer.

But, it seems reasonable that you can use what ever method you like, if the paper doesn't specify.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: July 3, 2012
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:
Today on TSR

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams