Using at least two peer-reviewed internet sites as references to answer the following question:
How has the use of fluoride in the community's water supply helped and it what ways has it been harmfull?

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