Doubt from work & Energy

work-power-energy
solved
find-velocity
dimensional-analysis
easy
pp
#1

Screenshot_2019-09-06-11-56-40-1-1

#2

I think length of rod should have been given.

#3

I did this ,the answer through this method is root 12 but the actual ans is 2.

#4

I am sharing some concepts downloaded ...pls go through it...Chain.pdf (68.7 KB)