Lesson 5 of 15
When the forces balance
Show on a big screenA book rests on a table. Is no force acting on it?
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Step 1 of 3
- Two equal pulls, opposite ways. Nothing is left over.
- The cart moves at a steady speed.
- The pulls stay equal, so the speed does not change.
The rule
Forces do act on the book. The Earth pulls it down. The table pushes it up. They cancel.
Forces are balanced when they cancel. The net force is zero. The motion does not change. Forces cancel when they are equal and opposite.
At rest means not moving. An object at rest still has forces on it. They balance one another.
Try the lab to finish this lesson.