Mechanics related question

[abc119]

Sir,
Please help me solve this question of mechanics. I cannot figure out what to do in this question.

[Fu-Kwun Hwang]

1. There is no torque so the angular momentum should be conserved: you can calculated the angular velocity (or tangential component of velocity) for the whole system when the sleeve just at the instant it get free. (You need to find the rotational inertia for the whole system first)
2. You can find the velocity in the radial direction from conservation of energy (No external force,too!).
3. You can calculate the total velocity with those two components calculated from the above steps.

[abc119]

Thank you sir. Now i am getting the correct answer of the question.

[Fu-Kwun Hwang]

What is important is not getting the correct answer, but understand the related physics concepts.
The limitation of the physics law and conditions which the law can be applied.
 

[waleed121]

If a car is driving at the speed of light and switches on its head-lights, what will happen?  Will the head-light still be able to "light" the areas in front?