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Home Concept Builders Newton's Laws Balanced vs. Unbalanced Forces Help Help 3

Balanced vs. Unbalanced Forces - Questions 3 Help

Force diagrams like the one shown depict the direction and strength of forces by vector arrows. Longer arrows mean stronger forces. One can determine if the forces are balanced by looking at the arrow size. Equal length arrows in opposite directions are required for forces to be considered balanced. Such situations are consistent with constant speed.

There are four similar versions of this question. Two of the versions include:
 

Version 1:

The diagram below represents the forces acting upon a rightward-moving object. Each arrow represents a force; the length of the arrow represents the strength of the force.

Is this object speeding up, slowing down, or moving at a constant speed?
Is this object experiencing balanced forces or unbalanced forces?



Version 2:

The diagram below represents the forces acting upon a rightward-moving object. Each arrow represents a force; the length of the arrow represents the strength of the force.

Is this object speeding up, slowing down, or moving at a constant speed?
Is this object experiencing balanced forces or unbalanced forces?

In these situations there is only one horizontal force. For horizontal forces to balance, every rightward force must be countered by an equal-strength leftward force. This is not the case in this situation. Thus the forces are unbalanced and an acceleration will occur.


Accelerations can involve either speeding up or slowing down motions. To determine which is occurring in this situation, first determine which way the objet is moving (read the first sentence). An object moving to the right will speed up if there is more force to the right than to the left. Objects moving to the right will slow down if there is more force to the left than to the right. Similar reasoning can be applied to leftward-moving objects.

State of Motion

Balanced and Unbalanced Forces
 

The Big Misconception

Concept Builder Teacher Notes Directions