1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Two masses connect by a rope over unequal slopes

  1. Sep 16, 2012 #1
    Hey Guys,

    I'm stuck with two particular problems that relates to two masses attached by a rope on a slope with unequal angles and i'm unsure how to go about the problem, I have never accounted a problem such as these before and i'm stuck with how to go about it. I have taken two photos of the questions as they include a diagram!

    Thanks in advanced.

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

    Q.9 and Q.19 are those I am refering to in the attachments.

    2. Relevant equations

    I believe looking at all the forces affecting the diagram, Tension, Gravity, Weight components, ultimately to my understanding ƩF=0 for the block to remain at rest, that is the forces balance. I am a bit confused on how to set out some of the forces as most problems I have encounted similar to this have a 90 degree angle where the block on the left is.

    3. The attempt at a solution

    I do not have answers to these two questions as they are not provided with the text book
     

    Attached Files:

  2. jcsd
  3. Sep 16, 2012 #2
    For each mass try writing sum of all forces in x and y direction. [and show us how you wrote them]

    Without going into calculations my intuition tells me the system will move to the left. [if there is no friction, can you tell what is the friction needed to keep the system at rest?]
     
  4. Sep 16, 2012 #3
    I don't know, i'm confused, I know the only possible forces that can act is tension and weight components but I don't know how to set it out. Here is an attempt anyway

    F1=F2

    F1:
    x: mgcosθ
    y: T-mgsinθ

    F2:
    x: T-mgcosθ
    y: T-mgsinθ
     
  5. Sep 16, 2012 #4
    1. Draw the system with all the forces, you don't need x and y as for both the masses all the relevant forces are in 1 dimension, choose the direction parallel to the slope. [in the other dimension sum of all forces are 0...]
    2. Don't forget the Newton laws.
    3. You will have 2 equations with two unknowns, do you know what they are?

    Let your intuition help you.
    Hint: What can you tell about a? [[itex]\sum F=ma[/itex]]
     
  6. Sep 16, 2012 #5
    Another hint, for each mass draw its own diagram and choose the coordinate system parallel to the slope.
     
    Last edited: Sep 16, 2012
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Two masses connect by a rope over unequal slopes
Loading...