Posted by HELP ME!! on Monday, April 19, 2010 at 11:08pm.
A playground merrygoround of radius 1.96 m has a moment of inertia 335 kg m2 and is rotating at 12.3 rev/min. A child with mass 43.1 kg jumps on the edge of the merrygoround. What is the new moment of inertia of the merrygoround and child, together? Answer in units of kg m2.

Physics Inertia : Merrygoround  bobpursley, Monday, April 19, 2010 at 11:12pm
add them: Inew=335 kg m^2+43.5*1.96^2 kg m^2

Physics Inertia : Merrygoround  HELP ME!!, Monday, April 19, 2010 at 11:22pm
Thank you, but what equation do you use? I cant seem to get the correct answer.What happens to the rev/min? Is it: inertia+child mass*radius^2

Physics Inertia : Merrygoround  bobpursley, Monday, April 19, 2010 at 11:27pm
The rev/min is not needed.
here is the equation:
momentofINertiatotal=momentinertiaMerryGoRound + momentinertiaKid.
Then you add them.
That is it. Now, if the problem goes on, you may need to find what the new angular speed is, but that is a different problem, you didn't ask that.

Physics Inertia : Merrygoround  nora, Friday, April 1, 2011 at 1:59pm
if you want to find the final angular speed, wf, you take:
momentinertiaMerryGoRound(initial angular speed) = (momentinertiaMerryGoRound + momentinertiaKid)(wf)
then solve for wf

Physics Inertia : Merrygoround  John, Thursday, May 7, 2015 at 7:25pm
Correct

Physics Inertia : Merrygoround  Ted, Sunday, April 24, 2016 at 5:55pm
What is the moment of inertia of the kid?
Answer This Question
Related Questions
 Physics: merrygoround question  A playground merrygoround of radius 1.92 m ...
 physics  A playground merrygoround of radius 2.00 m has a moment of inertia I...
 physics  A merrygoround in a playground has a mass of 200 kg and radius of 1....
 Physics  A playground merrygoround of radius R = 1.92m has a moment of ...
 physics  A playground merrygoround has a radius 2.6 m and a rotational ...
 physics  A merry go round in the park has a radius of 1.8 m and a rotational ...
 Physics  A playground merrygoround of radius R = 2.15 m has a moment of ...
 Physics  A 24.5kg child is standing on the outer edge of a merrygoround ...
 Physics  A merrygoround is rotating at 4.775 revs/min with a 45 kg child on ...
 Physics  A merrygoround in the park has a radius of 1.8 m and a rotational ...
More Related Questions