What do elements in the same group have? similar properties
the same atomic mass
the same number of electron shells
similar atomic numbers

The same number of electron shells, the atomic number is given to each individual element, same as the atomic mass, and properties have nothing to do with groups

Ke reqd to move from 0 to 50 will be proportional to 50x50 or 2500. this is equal to w.  to change vel from 50 to 150 you need energy prop to 22500 - 2500 = 20,000. this corresponds to 8w.  best answer is a) . work reqd is prop to velocity squared.