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Homework Help: Algodoo and Physics Analysis of Interactions

  1. Dec 3, 2017 #1
    1. The problem statement, all variables and given/known data

    I have created a very simple Rube Goldberg device in Algodoo, and I need to analyze 3 correlating steps within it, using physics descriptives and equations. My primary focus is the ball as it hits the windmill, which I need to describe and calculate its velocity at that stage. Next, I have to analyze the step prior to that: describing and solving for how the balls potential energy, kinetic energy, and momentum are changed during the descent through the ramps and how it translates to the next step; was the total energy conserved when it hit the windmill? Lastly, I need to describe the interaction as the ball after it hits the windmill - how its PE, KE and momentum changed during that interaction and how the total energy was conserved if at all and how it was transferred from one object to another, along with the final conservation of momentum throughout the 3 steps.

    2. Relevant equations

    PE = KE
    Momentum = Mass(Velocity)
    PE = (m)(g)(h)
    Not sure of others that may apply

    3. The attempt at a solution

    As you can see by the attached (I wish I could attach the .phz file to see it in motion), I created my simple machine in Algodoo which is the first part of the assignment. I have been trying to figuring out how to apply the above equations to the system but could not figure out where and how they could be applied, especially since the motion is not singular but contains multiple motions within a set (bouncing back and forth, free falling, projectile, etc). Any help you could provide by steering me in the right direction would be extremely helpful. Mahalo in advance.

    Attached Files:

    Last edited by a moderator: Dec 3, 2017
  2. jcsd
  3. Dec 6, 2017 #2
    With so many on here, can no one assist with suggestions ? I could really use some direction please? Anyone?
  4. Dec 6, 2017 #3
    I might help you, but I have some questions

    1-Is there a friction in this system ?
    2-Are triangle blocks stationary or they move when the ball hits them ?
    3-Whats the angle of the triangle blocks respect to an axis which, you ll use it to solve the problem ?
    4-Windmill moves with constant angular velocity right ?

    If we consider all system is frictionless, triangle blocks are stationary and If we know the angles of the blocks then it seems solvable to me.

    If there's friction or triangles blocks are moving then we need to consider something else and it will be more complicated.

    We need numericals for some data like height of the windmill, the angular velocity of the windmill etc. or we need to assign some symbols for them to solve the problem.
  5. Dec 6, 2017 #4
    Aloha Arman,

    Ohmygosh...Thank you in advance for answering the call!! ANY input is greatly appreciated!

    To answer your questions:

    1- No air friction and no notable friction on triangles.
    2- They are stationary.
    3- Left triangles show -15 degrees and the right triangles show -165 degrees at the x axis

    We can estimate the windmill to be 3 meters to top of the triangle, it has an angular velocity of -1.57 rad/s. Also, initial drop height of ball can be estimated to be approximately 25.5m.

    Do you have access to Algodoo or can you open a .phz file? If so, I can send you the file to evaluate in motion if it is permissible, I am not sure the rules on that type of thing but this forum does not allow for this type of file.

  6. Dec 7, 2017 #5
    We can start with KE energy and PE, until the ball hits the windmill.

    During this time we can try to understand the energy conservation and also the momentum of the ball.

    Since theres no friction we know that energy will conserved in this process. So we have a ball falling down and its potential energy will turn to kinetic energy in this process. Using the energy conservation can you find the velocity of the ball at the last triangle block. For direction of the velocity you can use momentum of the ball. Since the triangle blocks are stationary using the momentum conservation try to calculate an angle where in the last triangle what could be the angle of the ball.
  7. Dec 7, 2017 #6
    I am unsure as to how to find the angle of the ball, but upon impact to the last triangle, the velocity of the ball was noted in 3 directions: -5.77 m/s South, 6.37 m/s Southeast and 2.72 m/s East. Upon impact to the windmill, v = -12.07 m/s South, 12.23 m/s Southwest and -1.98 m/s West.

    Mass of ball is .461g

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