College Physics
posted by Paige .
A freely rotating merrygoround on a playground has a moment of inertia of 312 kgm2 and a radius of R=2.5 m. It is rotating with ω0=2.8 rad/s when a kid of mass 45 kg is standing on its outer rim. Neglecting friction, what is going to be the angular velocity of the merrygoround after she walked d=0.7 m toward the center?

I before: 312
I after: 31245(2.5.7)^2
conservation of momentum applies
momentumbefore=momentum after
312wo=(31245(2.5.7)^2)wf
solve for wf 
So would I divide the problem by wf?
Respond to this Question
Similar Questions

Physics Inertia : Merrygoround
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 … 
Physics: merrygoround question
A playground merrygoround of radius 1.92 m has a moment of inertia 411 kg m2 and is rotating at 10.4 rev/min. A child with mass 38.3 kg jumps on the edge of the merrygoround. Assuming that the boy's initial speed is negligible, … 
PHYSICS HELP!
A 3.6 m diameter merrygoround is rotating freely with an angular velocity of 0.78 rad/s. Its total moment of inertia is 1700 kg\m^2. Four people standing on the ground, each of mass 62 kg, suddenly step onto the edge of the merrygoround. … 
Physics
A 3.6 m diameter merrygoround is rotating freely with an angular velocity of 0.78 rad/s. Its total moment of inertia is 1700 kg m^2. Four people standing on the ground, each of mass 62 kg, suddenly step onto the edge of the merrygoround. … 
physics
A 4.4 diameter merrygoround is rotating freely with an angular velocity of 0.63 . Its total moment of inertia is 1800 . Four people standing on the ground, each of mass 66 , suddenly step onto the edge of the merrygoround. 
rotational motion physics
A 3.7 m diameter merrygoround is rotating freely with an angular velocity of 0.63 rad/s. Its total moment of inertia is 1600 kg\cdot m^2. Four people standing on the ground, each of mass 70 kg, suddenly step onto the edge of the … 
College Physics
A 40 kg child is standing on the edge of a merrygoround in a playground. Before they were deemed too dangerous, these were quite common. They were just huge rotating platforms you could sit on while someone spun you around in uniform … 
Physics
A 3.6 diameter merrygoround is rotating freely with an angular velocity of 0.73 . Its total moment of inertia is 1600 . Four people standing on the ground, each of mass 60 , suddenly step onto the edge of the merrygoround.What … 
Physics
A 4.2 m diameter merry go round is rotating freely with an angular velocity of 0.8 rad/s. If its total moment of inertia is 1760 kg*m2, find the angular velocity of the merry go round when four people of 72 kg jump onto the edge of … 
physics
A playground merrygoround of radius 2.00 m has a moment of inertia I = 255 kg·m2 and is rotating about a frictionless vertical axle. As a child of mass 25.0 kg stands at a distance of 1.00 m from the axle, the system (merrygoround …