What is the third basic component of an exercise program that includes cardio and flexibility?

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

How many neutrons does plutonium -196 with an atomic number of 78.

An electron in an x-ray machine is accelerated through a potential difference of 1.00 × 104 v before it hits the target. what is the kinetic energy of the electron in electron volts?