Conservation of Angular Momentum on a Merry-Go-Round

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SUMMARY

The discussion focuses on the conservation of angular momentum in a scenario involving a merry-go-round with a radius of 1.94 m and a moment of inertia of 184 kg-m², initially spinning at an angular speed of 1.66 rad/s. Key calculations include determining the initial angular momentum of both the merry-go-round and a person with a mass of 76 kg running at a velocity of 4.1 m/s. The conversation highlights the need to calculate the centripetal force required for the person to hold on after jumping onto the ride, as well as the linear velocity upon exiting the ride. The equations used include L = Iω for angular momentum and L = mvR for the person's momentum.

PREREQUISITES
  • Understanding of angular momentum and its conservation principles
  • Familiarity with the moment of inertia and its calculation
  • Knowledge of centripetal force and its relevance in rotational motion
  • Ability to apply kinematic equations in circular motion
NEXT STEPS
  • Calculate the angular momentum of the merry-go-round using L = Iω
  • Determine the centripetal force required for the person to hold on using F = mv²/R
  • Analyze the linear velocity of the person upon exiting the merry-go-round using v = ωR
  • Explore the effects of varying mass and radius on angular momentum in similar systems
USEFUL FOR

Students studying physics, particularly those focusing on rotational dynamics, as well as educators seeking to enhance their understanding of angular momentum concepts in practical scenarios.

mrshappy0
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Homework Statement


A merry-go-round with a a radius of R = 1.94 m and moment of inertia I = 184 kg-m2 is spinning with an initial angular speed of ω = 1.66 rad/s. A person with mass m = 76 kg and velocity v = 4.1 runs on a path tangent to the merry-go-round. Once at the merry-go-round they jump on and hold on to the rim of the ride.
1)What is the magnitude of the initial angular momentum of the merry-go-round? 2)What is the magnitude of the initial angular momentum of the person 2 meters before they jump on the merry-go-round? 3)What is the magnitude of the initial angular momentum of the person just before they jump on to the merry-go-round? 4)What is the angular speed of the merry-go-round after the person jumps on? 5)Once the merry-go-round travels at this new angular speed, what force does the person need to hold on? 6)Once the person gets half way around, they decide to simply let go of the merry-go-round to exit the ride.
What is the linear velocity of the person right as they leave the merry-go-round?

Homework Equations



L=Iω
L=mvR

The Attempt at a Solution



So I was easily able to answer all the questions up to questions 5, and 6. I don't even know where to start with 5. It seems like it requires more than just angular momentum. #6 doesn't seem bad. My thought is that it would be the same speed regardless of where the person let's go of the ride. So I would just calculate the linear velocity from the angular velocity that i got from the earlier parts. This would be the speed he would exit the merry-go-round.
 
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I agree with all you say. In #5, I think you are asked for the centripetal force that must be overcome by hanging on.
 

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