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Home Concept Builders Newton's Laws Balanced vs. Unbalanced Forces Help Help 11

Balanced vs. Unbalanced Forces - Questions 11 Help

When the forces acting upon an object are balanced, the object will maintain its state of motion; that is, its velocity remains constant. If the forces are unbalanced, the object will either speed up or slow down. The reverse logic is also true: if an object has a constant velocity, then the forces are balanced. And if an object is speeding up or slowing down, the forces are unbalanced.

There are six similar versions of this question. Three of the versions include:
 

Version 1:

The motion of an object is represented by position-time data.


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 motion of an object is represented by position-time data.


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

 


Version 3:

The motion of an object is represented by position-time data.


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

These questions describe an object's motion in terms of position-time data. By inspecting how the position changes over the course of time, one can tell whether the object is moving with a constant speed, slowing down, or speeding up.


In some of the instances, the position values will be increasing. In other instances, the position values will be decreasing. None of this matters. What does matter is the amount by which the numbers increase from one second to the next second. By inspecting several rows of data, one can determine how the object is moving. Here's what to look for:

If over the course of time, the changes in position (not the position, but the changes in position) are becoming bigger and bigger changes, then the object is speeding up. For instance, position values changing from 1.0 m to 2.0 m, to 4.0 m, to 8.0 m, etc. are showing changes that are becoming bigger and bigger. This is a speeding up motion; it is caused by an unbalanced force.

Now if over the course of time the changes in position are becoming smaller and smaller, then the object is slowing down. For instance, if the position values change from 1.0 m to 5.0 m to 8.0 m to 10.0 m, etc., then the changes from one value to the next are becoming smaller and smaller changes. This is a slowing down motion; it is also caused by an unbalanced force.

Finally, a constant speed motion would be displayed by position values which change by the same amount from one second to the next second. Constant speed motion is characteristic of a balance of forces.

One final note, when considering these changes, ignore +/- signs. Consider absolute values only.

Acceleration

State of Motion
 

Balanced and Unbalanced Forces
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