G.C.E. O/L Physics · Grade 10
Turning Effect of Forcesவிசையின் திரும்பல் விளைவுබලයක භ්රමණ ආචරණය
விசையின் திரும்பல் விளைவுබලයක භ්රමණ ආචරණය
Torque, principle of moments, clockwise vs anticlockwise moments, and levers. This page is a free preview of the STEM Cloud lesson for Grade 10 G.C.E. Ordinary Level Physics in Sri Lanka: the key points, the formulas, a worked example and a short quiz, taken from the lesson itself.
What you will learn
- A Force Can Turn Things Too!ஒரு விசை பொருளை திருப்பவும் செய்யும்!බලයකට දේවල් හැරවිය හැකියි!
- How Do You Calculate a Moment?திருப்பத்தை கணக்கு போடுறது எப்படி?ඝූර්ණයක් ගණනය කරන්නේ කෙසේද?
- Equilibrium — How a See-Saw Balancesசமநிலை — சீசா (see-saw) பாலன்ஸ் ஆவது எப்படி?සමතුලිතතාව — සීසෝවක් සමතුලිත වන ආකාරය
- Couple — Turning with a Pair of Forcesவிசை இணை (Couple) — இரட்டை விசையால் திருப்புறதுබල යුග්මය — බල යුගලයකින් හැරවීම
Key points to remember
- The turning (or rotating) effect produced about a point or an axis when a force acts on an object is called the moment of the force (turning effect).ஒரு பொருள் மேல விசை தாக்கும்போது, ஒரு புள்ளிய அல்லது அச்சப் பத்தி உண்டாகும் சுழற்சி விளைவு, அந்த விசையோட திருப்பம்.වස්තුවක් මත බලයක් ක්රියා කරන විට ලක්ෂ්යයක් හෝ අක්ෂයක් වටා ඇතිවන භ්රමණ (හැරවීමේ) ආචරණය බලයේ ඝූර්ණය (භ්රමණ ආචරණය) ලෙස හැඳින්වේ.
- Moment of a force = force × perpendicular distance from the pivot to the line of action of the force. Its unit is N m.விசையின் திருப்பம் = விசை × சுழல் புள்ளியில இருந்து விசையோட தாக்கக் கோட்டுக்கு உள்ள செங்குத்துத் தூரம். அலகு N m.බලයක ඝූර්ණය = භ්රමණ ලක්ෂ්යයේ සිට බලයේ ක්රියා රේඛාවට ලම්බ දුර × බලය. එහි ඒකකය N m වේ.
- Applying a couple is the easiest way to turn (or rotate) an object in a given direction.ஒரு பொருள ஒரு குறிப்பிட்ட திசையில திருப்ப (சுழற்ற) இணைய பிரயோகிக்கறதுதான் ரொம்ப எளிது.බල යුග්මයක් යෙදීම යනු වස්තුවක් දී ඇති දිශාවකට හැරවීමට (හෝ භ්රමණය කිරීමට) පහසුම ක්රමයයි.
- A couple is a pair of equal, parallel forces acting in opposite directions on the object.இணைன்னா பொருள் மேல எதிர்த் திசையில தாக்கும் சமமான, சமாந்தரமான இரு விசைகள்.බල යුග්මයක් යනු වස්තුව මත ප්රතිවිරුද්ධ දිශාවලට ක්රියා කරන සමාන, සමාන්තර බල යුගලයකි.
Key formulas
Moment of a forceவிசையின் திருப்பம்බලයේ ඝූර්ණය
விசையின் திருப்பம்බලයේ ඝූර්ණය
moment = F × d
- F = forceவிசைබලය (N)
- d = perpendicular distance from the axis to the forceஅச்சிலிருந்து விசைக்கான செங்குத்துத் தூரம்අක්ෂයේ සිට බලයට ලම්බ දුර (m)
20 N on a spanner, 0.5 m from the nut: moment = 20 × 0.5 = 10 N mநட்டிலிருந்து 0.5 m இல் 20 N: திருப்பம் = 20 × 0.5 = 10 N mඇණයේ සිට 0.5 m දී 20 N: ඝූර්ණය = 20 × 0.5 = 10 N m
Moment of a coupleவிசை இணையின் திருப்பம்බල යුග්මයක ඝූර්ණය
விசை இணையின் திருப்பம்බල යුග්මයක ඝූර්ණය
moment = F × d
- F = one of the two equal forcesசமமான இரு விசைகளில் ஒன்றுසමාන බල දෙකෙන් එකක් (N)
- d = perpendicular distance between the two forcesஇரு விசைகளுக்கும் இடையிலான செங்குத்துத் தூரம்බල දෙක අතර ලම්බ දුර (m)
15 N on each side of a steering wheel 0.4 m across: 15 × 0.4 = 6 N m0.4 m அகல ஸ்டீயரிங்கின் இருபுறமும் 15 N: 15 × 0.4 = 6 N m0.4 m පළල සුක්කානමේ දෙපසින් 15 N බැගින්: 15 × 0.4 = 6 N m
A worked example
Worked Example · Ch.11, p.205பாட புத்தக உதாரணம் · பாடம் 11, ப. 205වැඩ කළ නිදසුන · 11 පරි., පි.205
(i) Moment = Force × distance = 4 N × 0.5 m
(ii) For balance: left moment = right moment, i.e. w × 0.4 = 4 × 0.5
Make w the subject: w = (4 × 0.5) ÷ 0.4
(i) திருப்பம் = விசை × தூரம் = 4 N × 0.5 m
(ii) சமநிலைக்கு: இடப்புற திருப்பம் = வலப்புற திருப்பம், அதாவது w × 0.4 = 4 × 0.5
w-ஐ தனியே எடு: w = (4 × 0.5) ÷ 0.4
(i) ඝූර්ණය = බලය × දුර = 4 N × 0.5 m
(ii) සමතුලිතතාවට: වම් ඝූර්ණය = දකුණු ඝූර්ණය, එනම් w × 0.4 = 4 × 0.5
w උක්ත කරන්න: w = (4 × 0.5) ÷ 0.4
Try 5 quiz questions
A door is pushed at a point far from its hinge. Compared to pushing near the hinge, this needs...ஒரு கதவை மூட்டிலிருந்து தூரமான புள்ளியில் தள்றோம். மூட்டுக்கு அருகில் தள்றத ஒப்பிட்டா, இதுக்கு தேவை...
- A More forceஅதிக விசைවැඩි බලයක්
- B Less forceகுறைவான விசைඅඩු බලයක්
- C The exact same forceசரியா அதே விசைහරියටම එම බලයම
- D No force at allவிசையே தேவையில்லකිසිම බලයක් නැත
Show the answer
Answer: B. Less forceகுறைவான விசைඅඩු බලයක්
Moment = Force × distance from the axis. A bigger distance means less force is needed to produce the same moment.திருப்பம் = விசை × அச்சிலிருந்து தூரம். தூரம் அதிகமா இருந்தா, அதே திருப்பத்துக்கு குறைவான விசை போதும்.ඝූර්ණය = බලය × අක්ෂයේ සිට දුර. වැඩි දුරක් යනු එකම ඝූර්ණය ඇති කිරීමට අඩු බලයක් අවශ්ය බවයි.
A 6 N force acts at a perpendicular distance of 3 m from a pivot. What is the moment?6 N விசை ஒரு பிவாட்டிலிருந்து 3 m செங்குத்துத் தூரத்தில் தாக்குது. திருப்பம் என்ன?
- A 2 N m2 N m
- B 9 N m9 N m
- C 18 N m18 N m
- D 18 N18 N
Show the answer
Answer: C. 18 N m18 N m
Moment = Force × distance = 6 × 3 = 18 N m. Don't forget the unit is N m, not N!திருப்பம் = விசை × தூரம் = 6 × 3 = 18 N m. அலகு N m தான், N இல்ல!ඝූර්ණය = බලය × දුර = 6 × 3 = 18 N m. ඒකකය N නොව N m බව අමතක නොකරන්න!
A rod balanced at its centre has a 12 N weight at 2 m on the left. What force at 3 m on the right keeps it balanced?நடுவில் சமநிலைப்படுத்தப்பட்ட ஒரு கோலின் இடப்புறம், 2 m தூரத்தில் 12 N நிறை உள்ளது. வலப்புறம் 3 m தூரத்தில் என்ன விசை இருந்தால் சமநிலை இருக்கும்?
- A 4 N4 N
- B 8 N8 N
- C 18 N18 N
- D 36 N36 N
Show the answer
Answer: B. 8 N8 N
For balance: 12 × 2 = F × 3, so F = 24 ÷ 3 = 8 N.சமநிலை: 12 × 2 = F × 3, அதனால் F = 24 ÷ 3 = 8 N.සමතුලිතතාවට: 12 × 2 = F × 3, එබැවින් F = 24 ÷ 3 = 8 N.
Which of these correctly describes a 'couple'?இதுல எது ‘விசை இணை&rsquo் (couple)யை சரியா விவரிக்குது?
- A Two equal forces in the same directionஒரே திசையில் இரு சம விசைகள்එකම දිශාවට සමාන බල දෙකක්
- B Two equal, opposite, parallel forces not along the same lineஒரே நேர்கோட்டில் இல்லாத, சமமும் எதிர் திசையும் சமாந்தரமுமான இரு விசைகள்එකම රේඛාවක නොමැති සමාන, ප්රතිවිරුද්ධ, සමාන්තර බල දෙකක්
- C Any two forces acting on an objectஒரு பொருள் மேல தாக்கும் எந்த இரு விசைகளும்වස්තුවක් මත ක්රියා කරන ඕනෑම බල දෙකක්
- D A single force applied twiceஒரு விசையை இரண்டு தடவை பிரயோகித்தல்එක් බලයක් දෙවරක් යෙදීම
Show the answer
Answer: B. Two equal, opposite, parallel forces not along the same lineஒரே நேர்கோட்டில் இல்லாத, சமமும் எதிர் திசையும் சமாந்தரமுமான இரு விசைகள்එකම රේඛාවක නොමැති සමාන, ප්රතිවිරුද්ධ, සමාන්තර බල දෙකක්
A couple is specifically two equal, parallel, opposite forces that don't act along the same line — this produces pure rotation with no net force.விசை இணை என்பது சரியாக ஒரே நேர்கோட்டில் இல்லாத, சமமும் எதிர்திசையும் சமாந்தரமுமான இரு விசைகள் — இது நிகர விசை இல்லாம, சுத்த திருப்பத்த மட்டும் உண்டாக்கும்.බල යුග්මයක් යනු එකම රේඛාවක ක්රියා නොකරන සමාන, සමාන්තර, ප්රතිවිරුද්ධ බල දෙකකි — මෙය ශුද්ධ බලයක් නැතිව පිරිසිදු භ්රමණයක් ඇති කරයි.
An 8 m beam is balanced with three forces. If it's in equilibrium, what is the net moment about any random point on the beam?8 m கீற்று மூன்று விசைகளால் சமநிலையில் இருக்குது. இது சமநிலையில் இருந்தா, கீற்றின் மேல் எந்த ஒரு புள்ளியை பற்றியும் நிகர திருப்பம் என்ன?
- A It depends on which point you chooseஎந்த புள்ளியா தேர்ந்தெடுக்குறோமோ அதை பொறுத்ததுඑය රඳා පවතින්නේ ඔබ තෝරන ලක්ෂ්යය මත ය
- B Always zeroஎப்பவுமே பூச்சியம்සෑම විටම ශුන්යයි
- C Equal to the largest forceமிகப்பெரிய விசைக்கு சமம்විශාලතම බලයට සමාන
- D Cannot be determinedகண்டுபிடிக்க முடியாதுතීරණය කළ නොහැක
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Answer: B. Always zeroஎப்பவுமே பூச்சியம்සෑම විටම ශුන්යයි
If a system is in full equilibrium, the net moment about ANY point — not just the pivot — is always zero.ஒரு அமைப்பு முழுசமநிலையில் இருந்தா, எந்த ஒரு புள்ளியை பற்றியும் — பிவாட் மட்டுமல்ல — நிகர திருப்பம் எப்பவும் பூச்சியம்தான்.පද්ධතියක් සම්පූර්ණ සමතුලිතතාවයේ නම්, භ්රමණ ලක්ෂ්යය පමණක් නොව ඕනෑම ලක්ෂ්යයක් වටා ශුද්ධ ඝූර්ණය සෑම විටම ශුන්ය වේ.
In Tamil and Sinhala · தமிழில் · සිංහලෙන්
Every STEM Cloud lesson is in Tamil, English and Sinhala. The chapter's words, as the lesson uses them:
ஒரு பொருள் மேல விசை தாக்கும்போது, ஒரு புள்ளிய அல்லது அச்சப் பத்தி உண்டாகும் சுழற்சி விளைவு, அந்த விசையோட திருப்பம்.
වස්තුවක් මත බලයක් ක්රියා කරන විට ලක්ෂ්යයක් හෝ අක්ෂයක් වටා ඇතිවන භ්රමණ (හැරවීමේ) ආචරණය බලයේ ඝූර්ණය (භ්රමණ ආචරණය) ලෙස හැඳින්වේ.
- Moment of force · விசையின் திருப்பம் · බලයේ ඝූර්ණය
- Turning effect of a force · திருப்பல் விளைவு · බලයේ භ්රමණ ආචරණය
- Couple of force · விசை இணை · බල යුග්මයක්
In the full lesson
The full Turning Effect of Forces lesson walks through every step: the cartoon animation, the notes, all 2 worked examples, the virtual lab, the games and all 5 quiz questions. It opens with an account.
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Questions about Turning Effect of Forces
Is Turning Effect of Forces in the G.C.E. O/L Physics syllabus?
Yes. Turning Effect of Forces is a Grade 10 unit of G.C.E. Ordinary Level Physics in Sri Lanka, and STEM Cloud teaches it in the same order as the course map.
What are the key points of Turning Effect of Forces?
The turning (or rotating) effect produced about a point or an axis when a force acts on an object is called the moment of the force (turning effect). Moment of a force = force × perpendicular distance from the pivot to the line of action of the force. Its unit is N m. Applying a couple is the easiest way to turn (or rotate) an object in a given direction.
What are the common mistakes in Turning Effect of Forces?
"Distance" always means perpendicular distance! If a force acts at an angle, don't use the plain distance — use the distance measured at a right angle (90°) from the axis to the force's line of action. Don't forget clockwise vs anticlockwise. In balance problems, add up moments on one side and set them equal to the other side — don't wrongly lump everything together as if it's all the same direction. A couple has no net force, but it DOES have a net moment. Because the two forces are equal and opposite, they don't push/pull the object anywhere — but they still turn it. The unit of moment is N m — not N! Force alone is in N, but the moment of a force is always in N m (newton-metre).
Can I study Turning Effect of Forces in Tamil or Sinhala?
Yes. Every STEM Cloud lesson is in Tamil, English and Sinhala, and you can switch the language at any time from the lesson header.
How do I get the full Turning Effect of Forces lesson?
Sign up on the sign-up page, or message the admin on WhatsApp at 077 676 8865. You can try a free lesson first: Motion in a Straight Line.