PHYSICS HELP!
posted by Lacey on .
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.
1. What is the angular velocity of the merrygoround now?
2. What if the people were on it initially and then jumped off in a radial direction (relative to the merrygoround)?

What do you think the answer is?

I keep getting 0.68 ?????

I get something close to that.

Total kinetic energy
= (1/2)Iω²
ω1=0.78 rad/s
I1=1700 kgm²
I2=1700+4*(62*1.8²)=2503.5
(1/2)I1ω1²=(1/2)I2ω2²
Solve for
ω2
=√(I1/I2)ω1
=0.64 rad/s.
Check my calculations.