Two discs are rotating about an axis as shown in the figure. The moment of inertia of the right disc is 2 kg m2 and it rotates with angular speed of 2000 rpm. The

moment of inertia of the left disc is 5 kg m2 and it rotates in the opposite direction

with angular speed of 100 rpm. The discs are suddenly clamped together.

Determine the final common angular speed of the clamped discs.

Explanation:

Conservation of angular momentum

2(2000) + 5(-100) = (2 + 5)ω

ω = 500 rad/s

as the result is positive, the direction is in the same direction as the originally 2000 rad/s motion which we had assumed as the positive direction

positive reinforcement? ?

another example of kinetic energy would be,

kinetic energy   >     moving energy

answer   >   letter choice (c),   a hammer falling off a table.

hope that !                                         : )