SME
Grade 3 Science · Physical Science
Balanced and unbalanced forces
Use this for “One side pushes with 20 N and the other with 15 N. Which way does the box move?”
Diagram
Unbalanced: the box moves right.
This is an example. Type your own values to start a new problem.
Push to the right
example
Push to the left
example
Extra push
calculated
Formulas
20 and 15 are 5 apart
Difference between push to the right and push to the left = extra push
Assumptions
•
A force is a push or a pull. A spring scale measures it in newtons (N).
•
Two pushes on opposite sides are balanced when they are equal: the box stays still.
•
On a smooth floor, when one push is bigger, the box moves that way. The extra push is the difference.
Step-by-step
WE KNOW
Push to the right: 20 N
Push to the left: 15 N
FIND
extra push
Step 1 · Find extra push
20 and 15 are ? apart
Difference between push to the right and push to the left = extra push
The bigger push wins. The extra push is the bigger push take away the smaller one.
Extra push = 20 − 15
20 − 10 = 10
10 − 5 = 5
Extra push = 5 N (the push to the right is bigger)
Check
Put the numbers back in. Both sides should match.
20 − 15 = 5 ✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.