. Define 1 watt power

Which of these describe conduction transfer of heat between two objects that are touching transfer of heat by the actual movement of war matter the process in which energy is imitated by one of the object transmitted through space and absorbed by another a process in which energy is released by the molecules breaking apart

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

Four identical lab carts each have a mass of 200 kg. different masses are added to the carts and the velocities are measured. all carts move to the right.