we are doing a science proect on forces and energy.One of our science questions is how to make a cart go with just a rubber band. My first way of trying would be to tie the rubber band to the cart and pull the rubber band back and let go and the cart will go forward. This would be using elastic force. Theres many other ways to mke the cart go and you can figure that out your own. The difference between mass and weight is mass is the amount of the product and weight is the amount of the mass weighed.