What is the Angular Momentum of Harry Potter on a Spinning Merry-Go-Round?

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SUMMARY

The discussion focuses on calculating the angular momentum of Harry Potter while he is glued to a spinning merry-go-round. Given Harry's mass of 50.0 kg and a maximum acceleration of 5g, the key equations used are L = mvr and T = I alpha. The participants clarify that to find the angular momentum, the velocity (v) must be determined using the relationship between centripetal acceleration and velocity, specifically a = v²/r. The final angular momentum can be calculated once v is established.

PREREQUISITES
  • Understanding of angular momentum (L = mvr)
  • Knowledge of centripetal acceleration (a = v²/r)
  • Familiarity with rotational dynamics (T = I alpha)
  • Basic physics concepts such as mass and acceleration
NEXT STEPS
  • Calculate angular momentum using specific values for velocity and radius
  • Explore the relationship between linear and angular acceleration
  • Study the effects of rotational motion on objects in physics
  • Learn about the principles of centripetal force in rotating systems
USEFUL FOR

Students studying physics, particularly those focusing on rotational dynamics and angular momentum calculations, as well as educators seeking examples of real-world applications of these concepts.

bazookajason
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Homework Statement


Harry Potter is sitting 2.0 meters from the center of a merry-go-round when Draco Malfoy casts a spell that glues
Harry in place and then makes the merry-go-round start spinning on its axis. Harry has a mass of 50.0 kg and can
withstand 5:0 g's of acceleration before passing out. What is the magnitude of Harry's angular momentum when
he passes out?


Homework Equations


T=I alpha
L=mvr


The Attempt at a Solution



Assuming that the spell is a force then rF = I alpha. And using alpha = a/r, we using the max acceleration of 5g that
5mgr = Ia/r
However I'm not sure where to go from this, how do i get v? as time is unknwon
 
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bazookajason said:

Homework Statement


Harry Potter is sitting 2.0 meters from the center of a merry-go-round when Draco Malfoy casts a spell that glues
Harry in place and then makes the merry-go-round start spinning on its axis. Harry has a mass of 50.0 kg and can
withstand 5:0 g's of acceleration before passing out. What is the magnitude of Harry's angular momentum when
he passes out?

Lets look at the second eqn you mentioned,
L=mvr
you have m,r. what you need is v

Now, what do you think the acceleration 5g is acting along (direction)?
 
oh i see mv^2/r = ma a=5g :D
thanks!
 

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