Physics of car racing

Today i tried to make mine and Jeremiah car faster

So what i did was blowed up a balloon and put  it on the car. 

                                       If it is the final what i would do is pull the stick the stick will release the

  the balloon and it will make it go faster.

And I would hope for the balloon too stop that will make the car stop. 

I will try too figure out how too stop it. 

I research how too make a car go faster and slower.