Answer:
a) Speed of the rod = 0.4m/s
b) The part b says what if ? how does your answer to part (a) change if the electric field is not perpendicular to the rod?
If the electric field is not perpendicular to the rod, then a rrsolution has to be don eon the x -axis by resolving with respect tp Cos theta, the value pf the speed will still remains the same.
Explanation:
The detailed and mathematical derivation is shown in the attachment.
Here since both children and merry go round is our system and there is no torque acting on this system
So we will use angular momentum conservation in this
now here we have
Now when children come to the position of half radius
then we will have
now from above equation we have