Sir what happenswith the ball when we drop a ball in the whole persent in the earth from north to south pole

The ball will keep on moving from North Pole to the south pole due to gravitational force initially the ball will have maximum acc. and velocity=0 as the ball move down approaching the centre acc. decreases and velocity increases at the centre acc.=0 and velocity will be maximum . Same will happen in the next half acc. will increase in -ve and velocity will decrease .And the ball can not come out of that tunnel . And this action will be endless.

The ball will perform an periodic motion or you can say SHM and will go endless. Its time period wipl be 5050 seconds. At the center of earth its acceleration will ne zero and at the end points its velocity will be zero.