Adisk is rotating with angular speed ω1=2.0 rad/s about axle. the moment of inertia of disk & axle is 0.47 kg m2. a second disk of moment of inertia 0.31 kg m2 is dropped onto first. if dropped disk is rotating in opposite direction of ω1 with angular velocity ω2=1.0 rad/s, find magnitude of angular velocity of combination of two disks. express your answer in rad/s.

 w = 0.808 rad / s

Explanation:

As indicated by the moment of inertia t the angular velocity of the disks we use the concept of conservation of the angular momentum, for this we define the system as formed by the two discs, therefore the torque during the crash is internal and the angular momentum is conserved

Let's write in angular momentum

Initial. Before impact

         L₀ = I₁ w₁ + I₂ w₂

Final. After the rock has stuck

          = (I₁ + I₂) w

The two discs are rotating in opposite directions, we consider the rotation of the first positive disc, so the angular velocity of the second is negative

          L₀ =

           I₁ w₁ - I₂ w₂ = (I₁ + I₂) w

           w = (I₁ w₁ - I₂ w₂) / (I₁ + I₂)

Let's calculate

          w = (0.47 2.0 - 0.31 1.0) / (0.47+ 0.31)

          w = 0.63 / 0.78

          w = 0.808 rad / s

in the direction of disc rotation 1

what question you dont ask a question

explanation:

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.