Balanced and unbalanced forces
Forces come in pairs and are measured in newtons. What matters is not whether forces act, but whether they cancel.
Part of your national curriculum
- Physics: motion and forces: Understand forces as pushes or pulls arising from the interaction between two objects, and balanced and unbalanced forces
Lesson overview
What you'll learn in this lesson
Describe balanced and unbalanced forces
Key learning points
- • Resultant force
- • Friction and drag
This lesson at a glance
- 25 minutes
- 13 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 13
Visual introductionPicture this
Balanced and unbalanced forces
Forces come in pairs and are measured in newtons. What matters is not whether forces act, but whether they cancel.
In a nutshell
Describe balanced and unbalanced forces
Explore the idea
Part 2 of 13
Learn
Resultant force
Balanced forces give zero resultant: the object stays still or keeps a constant speed. Unbalanced forces change speed or direction.
Explore the idea
Part 3 of 13
Learn
Friction and drag
Friction opposes motion between surfaces; drag opposes motion through fluids. Terminal velocity is reached when drag balances weight.
Reset break
Part 4 of 13
Pause
That's sitting 1 of 3 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 5 of 13
Quick check
Part 6 of 13
Quick check
Part 7 of 13
Reset break
Part 8 of 13
Pause
That's sitting 2 of 3 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 9 of 13
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 10 of 13
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
____ forces give zero resultant: the object stays still or keeps a constant speed.
____ forces change speed or direction.
____ opposes motion between surfaces; drag opposes motion through fluids.
Challenge round
Part 11 of 13
Game · Recall cards
Balanced forces mean the object…
Card 1 of 3
Mastery quiz
Part 12 of 13
Marked quiz
End of lesson quiz: Balanced and unbalanced forces
3 questions, marked with the reasoning shown. No timer.
1. Balanced forces mean the object…
2. Forces are measured in…
3. Terminal velocity happens when…
Lesson round-up
Part 13 of 13
Lesson round-up
Ready when you are
Quiz score
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Games
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Points this lesson
0
Best run
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Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 13 · Watch & discover
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Understand forces as pushes or pulls arising from the interaction between two objects, and balanced and unbalanced forces