A block initially at rest on a horizontal, frictionless surface is accelerated by a constant horizontal force of 5 newtons. if 15 joules of work is done on the bock by this force, the kinetic energy of the block increases by

This is a very scary question. After you get all tied up in knots puzzling

and pondering and scheming how you might be able to work out the answer,

you suddenly realize how easy it is, how much unnecessary information there

is in it, and how much good useful energy you wasted puzzling and pondering.

If 15 joules of work is done on the block, and there are no other forces on

it, and there is no friction, then the kinetic energy of the block increases

by 15 joules.