In 1947. Northrop Aircraft developed and built a deceleration sled to test the effects of extreme forces on humans and equipment. In this sled, a test pilot with a mass of 70.0 kg undergoes a sudden negative acceleration of 4.90x 102 m/s. This deceleration occurs over a distance of 8.05 m. How much work is done against the pilot's body during the deceleration?

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