Back to basics: ball bouncing

hey everyone i was wondering if i could get some help with my bouncing ball
i will be uploading my progress
right now im kind of stuck... i know something is wrong but not sure what

bouncing ball_01

here is the graph editor on the Y Tangent

ball bouncing _02
ok so i edited the curves a bit n this is wat i got
although im happier with it im  not sure if this is wat it should luk like :)

ball bouncing_03
is it done yet??
it seems done to me
i mean just the y axis movement part