Conservation of Angular Momentum on a Merry-Go-Round

In summary, a merry-go-round with a radius of 1.94 m and moment of inertia of 184 kg-m2 is initially spinning at 1.66 rad/s. A person with a mass of 76 kg and velocity of 4.1 runs on a path tangent to the ride, then jumps on and holds onto the rim. The initial angular momentum of the merry-go-round is equal to the product of its moment of inertia and angular velocity, while the initial angular momentum of the person is equal to the product of their mass, linear velocity, and radius of the ride. Once the person jumps on, the angular speed of the ride increases. To hold on, the person must overcome a centripetal force. When
  • #1
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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  • #2
I agree with all you say. In #5, I think you are asked for the centripetal force that must be overcome by hanging on.
 

FAQ: Conservation of Angular Momentum on a Merry-Go-Round

1. How does angular momentum affect the motion of a merry-go-round?

Angular momentum is a physical quantity that measures the rotational motion of an object. In the case of a merry-go-round, angular momentum affects its spinning motion and determines how fast the ride will rotate.

2. What is the conservation of angular momentum?

The conservation of angular momentum is a fundamental law of physics that states that the total angular momentum of a system remains constant, unless acted upon by an external torque. This means that the amount of angular momentum in a closed system will remain the same, even if the objects within the system change their rotational speed or direction.

3. How is angular momentum conserved on a merry-go-round?

On a merry-go-round, angular momentum is conserved through the principle of inertia. As the riders move closer to the center of the ride, their rotational speed decreases in order to maintain the same amount of angular momentum in the system. Conversely, when the riders move towards the outer edge, their rotational speed increases.

4. What factors can affect the conservation of angular momentum on a merry-go-round?

The main factor that affects the conservation of angular momentum on a merry-go-round is external torque. This can come from friction, air resistance, or any other external force that slows down or speeds up the rotation of the ride. Additionally, the distribution of mass on the merry-go-round and the distance of the riders from the center can also impact the conservation of angular momentum.

5. Why is the conservation of angular momentum important in understanding the motion of a merry-go-round?

The conservation of angular momentum is important in understanding the motion of a merry-go-round because it explains how the ride maintains its rotational motion and how changes in the system, such as the movement of riders, can affect the ride's speed and direction. It also helps us understand the role of external forces in altering the ride's rotational motion.

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