I have built a mousetrap car for physics however it will not start. It will only jump in place and then stops. A requirement for the project is that the car must be able to start with a marble is dropped on the trap meaning I am not able to remove ANYTHING from the trap. However when I set off the trap the car only jumps, as I have told you before. BUT when I pull back the snapper arm and set the string normal and DONT set the mousetrap, just letting the car go right afterwards, the car moves about 2 meters. This is a good thing but I NEED the car to be able to move when the trap is set off. Sorry if this is confusing but help please?