Wht is the mass number of 19k/39

Explain the comparisons between nature and packingtown that appears on pages 81 and 82 answer

Rank the automobiles based on the magnitude of the force needed to stop them, from largest to smallest.2000 kg car going 5m/s500 kg car going 20 m/s1000 kg car going20m/s500 kg car going10m/s1000 kg car going10/s4000 kg car going 5m/s 0 0 603

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