When describing how something moves we need to include , which is also a force.

The answer would be a

An atom's smaller negative particles are at a distance from the central positive particles, so the negative particles are easier to move. 

Answer body lying face up ;

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.