In order for work to take place the energy present must be related to the movement of the object.

a. the force applied must be a balanced force resulting in motion of the object.

b. the force applied must cause the movement of the object

c. in the same direction as the force.

d. the movement of the object must be the cause of the force.

This is another one of those muddy misleading questions, followed by

a muddy group of choices from which an answer must be selected.

a). is absurd. There's no such thing as a "balanced force", only

a balanced group of forces.

b). is probably the choice the question is aiming for.

c). is not so. The engines of an airplane do plenty of work lifting the plane

off the ground, although the force of the engines is never directed upward.

d). is really awkward. The object's motion is almost never the cause of the force.

The force is almost always the cause of the object's motion.

Now for the big 800-lb gorilla in the room: No moving object needs to be involved

in order for energy to be flowing or work to be getting done.

- - A radio wave radiates through space. Straighten out a wire coat-hanger and

stick it up in the air where the radio wave can pass by it. Electrical current flows

through the wire, and you can drain the electrical energy out the bottom of it.

- - A light bulb is shining. Some distance away, something it's shining on

gets warm, because of the heat energy that has shot across to it from the

light bulb and soaked into it.

- - A lightning bolt jumps from the ground to a passing cloud. Or, if you feel

more comfortable with it, a lightning bolt jumps from a cloud to the ground.

It doesn't matter. Either way, there's enough energy splashing around to

ignite houses, zap TVs and computers, melt concrete, vaporize water, and

light up a city. Although nothing is moving.