Objects on elastic: a newbie question about pivot joints, friction joints or applyforce?

Hi, 

I’ve looked all over for examples and help but i just don’t think i’m understanding it properly… should I be using pivot joints, friction joints or some thing else completely… maybe a constant applyforce?

Basically i would like to have a physics object starting at pointA. but when the user continually clicks a button, each button click applies an impulse to the physics object causing it to move.

I’m looking to have the physics object locked on the y-Axis and always try to return to its starting point. the physics object ideally would have to act as if tethered by a piece of elastic to starting pointA meaning the more impulses and the further away the object gets the more stretched the elastic would be meaning the using would have to click faster and faster to push the object further away.

then once the user stops clicking / applying impulses the object would return to rest at the starting point. I also need this to happen to multiple objects in various directions so i’ve set the gravity to 0.

I hope what i’m trying to achieve makes sense. I’ve looked at pivot joints, friction joints but think i’m missing something really obvious.

Any help or pointers would be greatly appreciated?