question on FORCE! someone please help me...

[ecmy-obsez]

k well ive got to do a catapult investigation..ive got a pot and im suppose to hold it back with an elastic band tied to a clamp and let go and see how far it travels. i know if i add more weight in the pot..it will travel less...but WHY?? i need some explanations..
and also if i pull the elastic band further it will travel more obviously..but i dont know why this is!
can anyone PLEASE help me?? its urgent..thanks a bundle!! =) =)

[rayveldkamp]

Applying a force to an object causes it to accelerate, Newton's 2nd law gives
F=ma
So for a fixed force, the acceleration of the object is given by
a=F/m so the larger the mass is, the less its acceleration, and hence it will travel a smaller distance than a smaller mass would.

Now the elastic band when stretched will experience a linear restoring force given by:
F=-kx, where k is a SPRING CONSTANT, and x is the distance "stretched", dont worry about the negative sign for this case.
Now from here you can see the further you pull the band back, i.e. increase x, the larger the force will be.

Hope this helps

Ray