His Ph.D. thesis ruled out the idea of a fifth force, a proposed long range modification of gravity.

Three light-minutes out, something that massed like a half-sized cruiser seemed to represent the enemy's idea of a forward defensive force.

To understand the idea of a restoring force, imagine a guitar string.

But he said the idea of an international force was being considered by his office and such a force would not necessarily operate in Colombia.

This is fundamentally different from conventional ideas of a fifth force, as it grows stronger relative to gravity at longer distances.

Africa is slowly warming to the idea of a regional joint force, but it's still all theory.

Frequently, the idea of an indirect force is extended to include forces carried by other objects.

"The idea of a combined commando force deployed in that region is well beyond their capabilities."

I find the idea of a selective force implausible.

I would like to say that, for the first time in many years, the idea of an international force is not out of the question.