Auniform disk turns at 5.00 rev/s around a frictionless spindle. a non-rotating rod, of the same mass as the disk and length equal to the disk’s diameter, is dropped onto the freely spinning disk. they then turn together around the spindle with their centers superposed. what is the angular frequency in of the rev/scombination?

Final angular speed equals 3 revolutions per second

Explanation:

We shall use conservation of angular momentum principle to solve this problem since the angular momentum of the system is conserved

After the disc and the dropped rod form a single assembly we have the final angular momentum of the system as follows

Equating initial and final angular momentum we have

Solving for we get

Thus no of revolutions in 1 second are 6π/2π

No of revolutions are 3 revolutions per second

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.