Systemic circulation requires help from which of the following bones, lungs, arteries and veins, or muscles

A6,600 kg train car moving at +2.0 m/s bumps into and locks together with one of mass 5,400kg moving at -3.0m/s. what is their final velocity? +0.50 m/s -1.0 m/s +2.5 m/s -0.25 m/s

Ineed the answers for these promblems i have

The earth exerts a gravitational force of 500 n on amy. what is amy’s mass in kg?