If blood is a mixture then why doesn’t it separate in the air before it hits the ground

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

Explain what it means to view something from a frame of reference. provide an example that illustrates your explanation. (4 points)

The movement of electrons between atoms is called an