Does a stretched rubber band have stored energy

An automobile of mass 2000 kg moving at 30 m/s is braked suddenly with a constant braking force of 10000 n. how far does the car travel before stopping?

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass

Which of the following are appropriate acceleration units?