Hey there Sign in to join this conversationNew here? Join for free

M1 Combining forces

Announcements Posted on
    • Thread Starter
    • 3 followers
    Offline

    ReputationRep:
    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.
    • 29 followers
    Offline

    Diagram would be useful.

    Apply the cosine rule in each case to get two simultaneous equations.
    • Thread Starter
    • 3 followers
    Offline

    ReputationRep:
    (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?
    • 29 followers
    Offline

    (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.

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?

    this is what you'll be called on TSR

  2. this can't be left blank
    this email is already registered. Forgotten your password?

    never shared and never spammed

  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
    your full birthday is required
  1. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide the button to the right to create your account

    Slide to join now Processing…

Updated: July 3, 2012
New on TSR

Naughtiest thing you did at school

Did you get away with it or were you punished?

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