Classical mechanic

thanx

dear these are notation at the point where we are dealibg the situation like in my diagram i denote only point A and B same way in your solution they are i and r

please tell me what is the diff between r suffix i and r suffix f

see attached

can you please explain in quite detaill how the substitution of PE and KE is did and also those in angular momentum with tthe help of diiagram

i hope u r getting my point......plz ask if u have doubts

as u can see first we apply conservation of energy to find out the velocity then conservation of angular momentum to find out angle.

because particle is moving in perabolic it's not possible to conserve linear momentum so we will apply conservation of angular momentum

dear must remember that to solve these type of problems.........we always know energy and momentum conservation.