in the above question I have doubt regarding validity of angular momentum conservation.

The question is solved by conserving angular momentum about axis of larger disc as follows ;

$$0 = -\frac{1}{2} M(\frac{R}{2})^2 w + M(Rw')R + \frac{1}{2} M(R^2)w' w'=\frac{w}{12}$$

but as the smaller disc is operated by motor  ,is angular momentum conserved when motor is turned on

For example: if two similar discs are put one on one, and one of them is operated by motor giving a constant angular velocity w ,both will move in same direction with w. and angular momentum is not conserved

please clear doubt.

in the above question I have doubt regarding validity of angular momentum conservation.

The question is solved by conserving angular momentum about axis of larger disc as follows;

$$0 = -\frac{1}{2} M(\frac{R}{2})^2 w + M(Rw')R + \frac{1}{2} M(R^2)w' w'=\frac{w}{12}$$

but as the smaller disc is operated by motor, is angular momentum conserved when motor is turned on

For example: if two similar discs are put one on one, and one of them is operated by motor giving a constant angular velocity $w $, both will move in same direction with $w$. and angular momentum is not conserved

please clear doubt.

in the above question I have doubt regarding validity of angular momentum conservation.

The question is solved by conserving angular momentum about axis of larger disc as follows ;

0 = -1/2 M(R/2)^2 w + M(Rw')R + 1/2 M(R^2)w'
w'=w/12

but as the smaller disc is operated by motor ,is angular momentum conserved when motor is turned on

For example: if two similar discs are put one on one, and one of them is operated by motor giving a constant angular velocity w ,both will move in same direction with w. and angular momentum is not conserved

please clear doubt.

in the above question I have doubt regarding validity of angular momentum conservation.

The question is solved by conserving angular momentum about axis of larger disc as follows ;

$$0 = -\frac{1}{2} M(\frac{R}{2})^2 w + M(Rw')R + \frac{1}{2} M(R^2)w' w'=\frac{w}{12}$$

but as the smaller disc is operated by motor ,is angular momentum conserved when motor is turned on

For example: if two similar discs are put one on one, and one of them is operated by motor giving a constant angular velocity w ,both will move in same direction with w. and angular momentum is not conserved

please clear doubt.