9th Class Physics Chapter 4 Online Test: 25 MCQs with Answers

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This 9th class physics chapter 4 online test covers Chapter 4 of the Class 9 Physics course, Turning Effects of Force. It has 25 multiple-choice questions, shown one at a time, and it marks itself as soon as you finish. There is no timer and no sign-up. When you press finish you get your score, and every question is shown again with your answer, the correct option and a short explanation of why that option is right. An Urdu medium version of the same test is given further down this page.

What Chapter 4 Covers

The questions are spread across the whole chapter rather than one section, so the test is a fair check of whether you are ready for a class test or the annual paper:

  • Resolution of forces — finding the horizontal and vertical components of a force acting at an angle.
  • Torque — moment of a force, its SI unit, why the turning effect is greater when the force acts further from the pivot, and why torque is zero when the line of action passes through the pivot.
  • Principle of moments — balancing a see-saw, and the shopkeeper’s balance with unequal arms.
  • Couples — two equal and opposite parallel forces, as when a steering wheel is turned with both hands.
  • Centre of gravity — where it lies in a uniform disc, and how a tightrope walker and balancing toys use it.
  • Equilibrium — the first and second conditions, and stable, unstable and neutral equilibrium with everyday examples.
  • Stability — why racing cars are wide and low, and why a double-decker bus loaded on the upper deck topples easily.
  • Circular motion — centripetal force, a stone whirled on a string, and what happens when the string breaks.

Revise These Before You Start

Most marks in this chapter are lost on the same few points. Read through these once before attempting the test:

  • Components of a force: horizontal = F cos θ and vertical = F sin θ, measured from the horizontal axis.
  • Torque = force × perpendicular distance from the pivot, measured in newton metres (N m). The distance must be perpendicular, not along the force.
  • Principle of moments: in equilibrium, the sum of clockwise moments equals the sum of anticlockwise moments.
  • For complete equilibrium both conditions must hold: the resultant force is zero and the resultant torque is zero.
  • Centripetal force Fᴄ = mv² ÷ r, so doubling the speed makes the force four times larger, while doubling the radius halves it.
  • When the string breaks, the stone flies off along the tangent, not outwards along the radius.

How the Test Works

  • 25 questions, one at a time, with Next and Previous buttons.
  • No timer, so you can work a numerical out on paper before answering.
  • Automatic marking the moment you finish.
  • Answer review with the correct option and an explanation for every question.
  • Retake as many times as you like, and your score is not stored anywhere.

Start the Chapter 4 Online Test

Chapter 4 mixes trigonometry with reasoning about balance, so check each answer by asking which distance is perpendicular and which component the question wants. Keep a pen and rough paper beside you: the numerical questions are quick, but they are much easier to get right written down than in your head. Aim for 20 out of 25 or better before you move on to the next chapter.

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Class 9 Physics Chapter 4 Online Test — Turning Effects of Force

25 multiple-choice questions from Chapter 4 of the Class 9 Physics course, with automatic marking, an answer review and explanations.

1 / 25

A force F is making an angle of 60° with the x-axis. Its y-component is equal to:

2 / 25

A shopkeeper sells his articles by a balance having unequal arms. If he puts the weights in the pan having the shorter arm, then the customer:

3 / 25

A man walks on a tight rope. He balances himself by holding a bamboo stick horizontally. It is an application of:

4 / 25

In stable equilibrium, the centre of gravity of the body lies:

5 / 25

A spanner 25 cm long is used to open a nut. If a force of 400 N is applied at its end, the torque acting on the nut is:

6 / 25

A 150 g stone tied to a string of length 1.2 m is whirled in a horizontal circle at a constant speed of 8 m s⁻¹. The centripetal force acting on it is:

7 / 25

A force of 160 N acts on a box at an angle of 60° with the horizontal. Its horizontal (x) component is:

8 / 25

When two equal and opposite parallel forces act at two different points of the same body, they form a:

9 / 25

Most balancing toys are stable because they have:

10 / 25

In a washing machine dryer, the centripetal force needed by the clothes is provided by:

11 / 25

A racing car is made with a wide base and a very low body mainly to:

12 / 25

A ball lying on a horizontal table is pushed slightly. It stays in its new position. The ball is in:

13 / 25

The first condition of equilibrium states that:

14 / 25

A body moving with uniform velocity in a straight line satisfies:

15 / 25

The turning effect produced by a force is greater when the force is applied:

16 / 25

The line of action of a force passes through the pivot of a body. The torque produced by this force is:

17 / 25

The SI unit of torque is:

18 / 25

The centre of gravity of a uniform circular disc lies:

19 / 25

Turning a steering wheel with both hands applied in opposite directions is an everyday example of a:

20 / 25

A stone tied to a string is whirled in a circle. If the string suddenly breaks, the stone will:

21 / 25

If the speed of a body moving in a circle is doubled while the radius stays the same, the centripetal force becomes:

22 / 25

A see-saw is balanced when a 30 kg child sits 2 m from the pivot. To balance it, a 40 kg child must sit at a distance of:

23 / 25

A double-decker bus carrying all its passengers on the upper deck is more likely to topple because:

24 / 25

For a body to be in complete equilibrium:

25 / 25

A cone standing upright on its pointed tip is an example of:

Your score is

0%

Chapter 4 Online Test — Urdu Medium

Urdu medium students can attempt the same Chapter 4 test with every question, option and explanation written in Urdu. It behaves exactly like the English test above: 25 questions one at a time, no timer, and a full answer review at the end.

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Class 9 Physics Chapter 4 Online Test (Urdu Medium) — Turning Effects of Force

Urdu medium online test, 25 MCQs with instant result and explanations.

1 / 25

ایک فورس F ایکس-ایکسس کے ساتھ 60° کا زاویہ بناتی ہے۔ اس کا y اجزا برابر ہے:

2 / 25

ایک دکاندار اپنا سامان غیر مساوی بازوؤں والی ترازو سے بیچتا ہے۔ اگر وہ باٹ چھوٹے بازو والے پلڑے میں رکھے تو گاہک:

3 / 25

ایک شخص تنی ہوئی رسی پر چلتا ہے۔ وہ بانس کو افقی پکڑ کر اپنا توازن برقرار رکھتا ہے۔ یہ کس کا اطلاق ہے؟

4 / 25

قیام پذیر توازن میں جسم کا سنٹر آف گریویٹی ہوتا ہے:

5 / 25

ایک 25 cm لمبا رنچ کسی نٹ کھولنے کے لیے استعمال ہوتا ہے۔ اگر اس کے سرے پر 400 N کی فورس لگائی جائے تو نٹ پر عمل کرنے والا ٹارک ہے:

6 / 25

150 g کا ایک پتھر ایک ڈوری کے ساتھ باندھ کر ایک افقی دائرے میں یکساں سپیڈ 8 m s⁻¹ سے گھمایا گیا ہے۔ ڈوری کی لمبائی 1.2 m ہے۔ پتھر پر عمل کرنے والی سنٹری پیٹل فورس ہے:

7 / 25

ایک 160 N کی فورس ایک ڈبے پر افقی سمت کے ساتھ 60° کے زاویے پر عمل کرتی ہے۔ اس کا افقی (x) اجزا ہے:

8 / 25

جب دو مساوی اور مخالف سمت میں متوازی فورسز ایک ہی جسم کے دو مختلف نقاط پر عمل کریں تو وہ بناتی ہیں:

9 / 25

زیادہ تر بیلنسنگ کھلونے مستحکم ہوتے ہیں کیونکہ ان کا ہوتا ہے:

10 / 25

واشنگ مشین ڈرائر میں کپڑوں کو درکار سنٹری پیٹل فورس کون فراہم کرتی ہے؟

11 / 25

ریسنگ کار کا قاعدہ چوڑا اور جسم بہت نیچا بنایا جاتا ہے، بنیادی مقصد ہے:

12 / 25

افقی میز پر پڑی ایک گیند کو ہلکا سا دھکا دیا جاتا ہے۔ وہ اپنی نئی پوزیشن پر ہی ٹھہر جاتی ہے۔ گیند کس توازن میں ہے؟

13 / 25

توازن کی پہلی شرط یہ بیان کرتی ہے کہ:

14 / 25

سیدھی لائن میں یکساں ولاسٹی سے حرکت کرنے والا جسم پورا کرتا ہے:

15 / 25

کسی فورس سے پیدا ہونے والا گھمانے کا اثر زیادہ ہوتا ہے جب فورس لگائی جائے:

16 / 25

کسی فورس کا لائن آف ایکشن جسم کے محور سے گزرتا ہے۔ اس فورس سے پیدا ہونے والا ٹارک ہے:

17 / 25

ٹارک کا SI یونٹ ہے:

18 / 25

ایک یکساں دائروی ڈسک کا سنٹر آف گریویٹی ہوتا ہے:

19 / 25

سٹیئرنگ وہیل کو دونوں ہاتھوں سے مخالف سمتوں میں گھمانا روزمرہ زندگی میں کس کی مثال ہے؟

20 / 25

ایک رسی سے بندھا پتھر دائرے میں گھمایا جا رہا ہے۔ اگر رسی اچانک ٹوٹ جائے تو پتھر:

21 / 25

اگر دائرے میں حرکت کرتے جسم کی سپیڈ دو گنی کر دی جائے جبکہ رداس وہی رہے تو سنٹری پیٹل فورس ہو جائے گی:

22 / 25

ایک سی-سا اس وقت متوازن ہے جب 30 kg کا بچہ محور سے 2 m کے فاصلے پر بیٹھا ہو۔ اسے متوازن رکھنے کے لیے 40 kg کے بچے کو بیٹھنا ہوگا:

23 / 25

ایک ڈبل ڈیکر بس جس کے تمام مسافر اوپر والی منزل پر ہوں، اس کے الٹنے کا امکان زیادہ ہوتا ہے کیونکہ:

24 / 25

کسی جسم کے مکمل توازن میں ہونے کے لیے:

25 / 25

اپنی نوکدار چوٹی پر سیدھا کھڑا ایک مخروط (کون) کس کی مثال ہے؟

Your score is

0%

Mistakes Students Make in This Chapter

When you check your answer review, see whether any of your wrong answers came from these. They account for most of the marks lost in this chapter:

  • Using sin where cos belongs when resolving a force, or measuring the angle from the wrong axis.
  • Taking the distance along the direction of the force instead of the perpendicular distance from the pivot.
  • Thinking a body moving at constant velocity is not in equilibrium, when in fact it satisfies both conditions.
  • Saying a whirled stone flies radially outwards when the string snaps.
  • Forgetting that doubling the speed quadruples the centripetal force, because of the v² term.

What to Do After the Test

Do not close the page as soon as you see your score. Read the explanation under every question you got wrong, then open that topic in your textbook and work through the solved example beside it. Write the questions you missed on a single sheet and attempt the test again the next day: the second score tells you what you have actually learned, while the first only tells you what you recognised. If you scored below 15, work through the chapter again before moving on, because the later chapters in Physics build directly on this one.

Frequently Asked Questions

What is the SI unit of torque?

The newton metre (N m). Torque is force multiplied by the perpendicular distance from the pivot, so its unit is the unit of force multiplied by the unit of distance. It is not the joule, even though the units look similar.

Why does a wide base make an object more stable?

A wide base lets the object tilt further before its centre of gravity passes outside the base. Until that point the weight pushes it back upright, which is why racing cars are built low and wide.

What happens when the string of a whirled stone breaks?

The centripetal force disappears, so the stone travels in the straight line it was moving along at that instant, which is the tangent to the circle. It does not fly outwards along the radius.

Related Class 9 Physics Resources

Work through the Chapter 4 exercise short questions for written practice. The Chapter 4 constructive questions cover the longer, reasoning-based answers. You can also browse all Class 9 Physics exercise short questions and constructive questions, or open the Class 9 Physics section, which brings notes, test papers, online papers, guess papers and past papers together chapter by chapter.

2 thoughts on “9th Class Physics Chapter 4 Online Test: 25 MCQs with Answers”

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