doubts on gravitation continued

Question

aravindg · Answer

a hole is drilled from the surface of the earth and a ball is thrown inside .the ball executes SHM why?

anonymous · Answer

Could you draw for the earth and this hole? I think I know what you mean but just to be sure

aravindg · Answer

|dw:1327507100491:dw|

aravindg · Answer

help pls

turingtest · Answer

The force acting on the falling object acts opposite direction of its displacement|dw:1329322341910:dw|toward the center of mass of the earth (the equilibrium position of the falling object)$$F_g\propto-x$$so there is always a restoring force acting to move the object toward the center of the earth. However when the object passes through the center point of the earth all the potential energy it started with is now kinetic, so it will pass through and gravity will act in the opposite direction. This will continue indefinitely unless a dampening force acts to slow the motion of the object.