Jenny is doing her homework. When Jenny wrights the pencil exerts a force of 5N on the paper the area of the pencil in contact with the paper is 0.5mm squared calculate the pressure kg the pencil on the paper. Give the unit

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. 

Assuming you're referring to significant figures, none of these answer choices are shown to be zero as significant digits. did you, by chance, forget to add something?