Awheel is rotating freely with an angular speed of 800 rev/min on a shaft whose rotational inertia is negligible. a second wheel, initially at rest and twice the rotational inertia of the first, is suddenly coupled to the same shaft. we have to find(a) the angular speed of the resultant combination of the shaft and the two wheels; (b) the fraction of the original rotational kinetic energy lost in the process.

a)

b)

Explanation:

Given:

rotational speed of the wheel 1,

Let the rotational inertia of the wheel 1 be,

According to given, the rotational inertia of wheel 2,

(a)

According to the law of conservation of angular momentum:

(b)

initial kinetic energy:

Final kinetic energy:

∴the fraction of the original rotational kinetic energy lost in the process:

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.