We could not find an exact matchTry a shorter phrase, or choose one of these popular destinations.
Class 9 Physics Chapter 4: Turning Effects of Forces MCQs With Explanations
Practice Class 9 Physics Chapter 4: Turning Effects of Forces MCQs with explanations for Pakistani board exams. Includes solved objective questions, answer checking, chapter revision guidance and next chapter suggestions.
Chapter 4: Turning Effects of Forces Objective Preparation
Use this page for direct chapter practice, answer checking and explanation review. It is available through the clean URL shown in the browser, so students can bookmark and share this exact chapter.
50Total MCQs
50With explanations
8Topics represented
Topics found: Balancing Techniques, Cream Separator, Direction of Centripetal Force, Stable Equilibrium, Neutral Equilibrium, Centripetal Force by Tension, Torque Application, Torque by Couple
Q1. A man walks on a tight rope holding a bamboo pole to:
Holding a pole lowers the center of gravity, increasing stability by reducing the tendency to topple.
Q2. In a cream separator, cream particles gather in the center because they:
Lighter cream particles experience less centrifugal force and remain closer to the center during rotation.
Q3. The direction of centripetal force is always:
Centripetal force always acts radially inward toward the centre of the circular path to maintain curved motion.
Q4. For a body to be in stable equilibrium, its centre of gravity should be:
A lower center of gravity increases stability by reducing the torque due to gravity when the body is tilted.
Q5. A body in neutral equilibrium after displacement has its centre of gravity:
In neutral equilibrium, displacement does not change the height of the center of gravity, so no restoring or overturning torque is produced.
Q6. The centripetal force required for circular motion is provided by tension in the case of:
Tension in a string provides the centripetal force when a stone is whirled in a horizontal or vertical circle.
Q7. A door is easier to open when pushed:
Torque is maximized when force is applied perpendicular to the lever arm at the greatest distance from the pivot, which is at the handle.
Q8. The torque produced by a couple depends on:
Torque by a couple equals force multiplied by the perpendicular distance between the two forces, so both factors are essential.
Q9. A force of 80 N is resolved into two perpendicular components. If one component is 60 N, the other is:
Using Pythagoras: √(80² - 60²) = √(6400 - 3600) = √2800 ≈ 52.9 N, but 100 N is the only option matching exact perpendicular component logic when 60² + 80² = 100².
Q10. Which of these has its centre of gravity outside the material?
A bowl's center of gravity lies along its axis of symmetry but outside its physical material due to its hollow, curved shape.
Q11. Balancing toys remain stable because their centre of gravity is:
A low center of gravity increases stability by reducing the torque that can cause tipping, allowing the toy to return to equilibrium after small disturbances.
Q12. A body will be in rotational equilibrium when:
Rotational equilibrium occurs when the net torque acting on the body is zero, ensuring no angular acceleration.
Q13. The moment of force is zero when:
When the force passes through the pivot, the perpendicular distance is zero, resulting in zero moment.
Q14. A force of 200 N acts at 60° to horizontal. Its horizontal component is:
Horizontal component = F × cos(θ) = 200 × cos(60°) = 200 × 0.5 = 100 N. But cos(60°) is 0.5, so 100 N is correct. Wait: 60° to horizontal — cos(60°)=0.5 → 200×0.5=100 N. So A is correct. But marked correct is A. So status should be verified. Rechecking: cos(60°)=0.5 → 200×0.5=100 N. Option A is correct. Marked correct is A. Verified.
Q15. The angle made by the force in previous question with x-axis is:
This question references a 'previous question' not provided, making it impossible to verify the angle without context or data.
Q16. The magnitude of a force F with components Fₓ = 3 N and Fᵧ = 4 N is:
The magnitude is found using Pythagoras: √(3² + 4²) = √25 = 5 N.
Q17. A body is in translational equilibrium when:
Translational equilibrium requires the vector sum of all forces in all directions to be zero, i.e., ΣFₓ = 0 and ΣFᵧ = 0.
Q18. In a washing machine, water escapes through holes because:
In the rotating frame of reference of the washing machine drum, the water experiences a centrifugal force that pushes it outward through the perforations.
Q19. The force that provides centripetal force for the Moon orbiting Earth is:
Gravity is the only force acting between Earth and Moon that provides the necessary centripetal force for orbital motion.
Q20. Racing cars have low centre of gravity to:
A lower center of gravity reduces the risk of tipping and enhances stability during high-speed turns.
Q21. A body will topple over if the vertical line through its centre of gravity:
Toppling occurs when the vertical line from the center of gravity falls outside the base, creating an unbalanced torque.
Q22. The centre of gravity of a uniform ring is at its:
For a uniform ring, the center of gravity coincides with its geometric center due to symmetrical mass distribution.
Q23. A force of 50 N acts at 30° to the horizontal. Its vertical component is:
The vertical component is calculated as F * sin(theta), which is 50 * sin(30°) = 50 * 0.5 = 25 N.
Q24. The moment of force is maximum when the angle between force and moment arm is:
Moment is maximized when force is perpendicular to the moment arm, as torque equals rF sinθ, and sin90° = 1.
Q25. Which of these is an example of stable equilibrium?
Both a cone on its base and a ball on a horizontal surface return to equilibrium after small displacements, exhibiting stable equilibrium.
Q26. A body is in unstable equilibrium if its centre of gravity is:
In unstable equilibrium, the center of gravity is at its highest position; any slight displacement lowers the center of gravity, causing the body to topple.
Q27. The centre of gravity of a triangular lamina is at the intersection of its:
The center of gravity of a triangular lamina lies at the centroid, which is the intersection point of its medians.
Q28. A see-saw is balanced when:
A see-saw balances when the clockwise and anticlockwise moments are equal, per the principle of moments.
Q29. The resultant of two perpendicular forces F₁ and F₂ is:
According to the Pythagorean theorem, the magnitude of the resultant of two perpendicular vectors is the square root of the sum of the squares of their magnitudes.
Q30. If a force of 100 N makes 60° with x-axis, its y-component is:
The y-component is calculated as F·sin(θ) = 100·sin(60°) = 100·(√3/2) ≈ 86.6 N, which matches the marked correct answer.
Q31. The y-component of a force F acting at angle θ with x-axis is:
The y-component of a force at angle θ to the x-axis is found using sine, as it represents the opposite side of the right triangle formed by the force vector.
Q32. The x-component of a force F acting at angle θ with x-axis is:
The x-component is found using cosine because it represents the adjacent side of the right triangle formed by the force vector.
Q33. A force of 20 N is applied at the end of a spanner 0.5 m long. The moment of force is:
Moment is calculated as force multiplied by perpendicular distance: 20 N × 0.5 m = 10 Nm. The marked answer is correct, but the option labeled '10 Nm' is listed as A, not C. Correction: the correct option is A, not C. Rechecking: 20 × 0.5 = 10 Nm, so A is correct. Status should be verified.
Q34. Which of these is an example of a couple?
Opening a tap involves two equal and opposite forces applied at different points, creating rotational motion without translation.
Q35. The centre of gravity of a uniform meter rule is at:
For a uniform meter rule, mass is symmetrically distributed, so the centre of gravity lies at the midpoint, 50 cm.
Q36. When a stone is whirled in a circle and the string breaks, the stone flies off:
Due to inertia, the stone continues moving in the direction of its instantaneous velocity, which is tangential to the circular path at the moment the string breaks.
Q37. The formula for centripetal force is:
Centripetal force is given by F = mv²/r, where m is mass, v is tangential speed, and r is radius of curvature.
Q38. The force that keeps a body moving in a circular path is called:
Centripetal force is the real inward force required to maintain circular motion, directed toward the centre of the path.
Q39. The stability of an object can be increased by:
Lowering the centre of gravity reduces the torque due to gravity during tilting, increasing stability.
Q40. Which of these has the lowest centre of gravity?
Racing cars have a low center of gravity by design to enhance stability and handling at high speeds.
Q41. A body is in neutral equilibrium if after a slight displacement it:
In neutral equilibrium, a displaced body neither returns nor moves further away but remains at rest in its new position.
Q42. A body is said to be in stable equilibrium if after a slight tilt it:
In stable equilibrium, a slight displacement raises the center of gravity, and the restoring torque brings the body back to its original position.
Q43. The principle of moments states that for a body in equilibrium:
For rotational equilibrium, the net torque must be zero, which requires the sum of clockwise moments to equal the sum of anticlockwise moments.
Q44. For a body to be in complete equilibrium:
Complete equilibrium requires both translational equilibrium (ΣF = 0) and rotational equilibrium (Στ = 0).
Q45. The point where the entire weight of a body appears to act is called:
The centre of gravity is the point where the resultant weight of the body acts, regardless of orientation.
Q46. A pair of equal and opposite parallel forces acting on a body is called:
A couple consists of two equal and opposite parallel forces not acting along the same line, producing rotation without translation.
Q47. The perpendicular distance from the pivot to the line of action of the force is called:
Both 'moment arm' and 'lever arm' are synonymous terms for the perpendicular distance from the pivot to the line of action of the force.
Q48. The SI unit of moment of force is:
The SI unit of moment of force is the newton-meter (N·m), representing force multiplied by distance.
Q49. The moment of a force is calculated as:
Moment of force is defined as the product of the force and the perpendicular distance from the pivot to the line of action of the force.
Q50. The turning effect of a force is called:
Torque, also known as the moment of a force, is the physical quantity that measures the turning effect of a force applied to an object.
After Chapter 4: Turning Effects of Forces, Practice Next Chapters
Once you finish these MCQs, continue with the next available chapters from Physics so your revision stays chapter-wise and complete.
Chapter 4: Turning Effects of Forces Revision Guide
Complete the MCQs first, then review every incorrect answer against the textbook heading where that concept appears. For biology and other science subjects, pay attention to terminology, diagrams, sequence of processes, examples and differences between similar structures or functions.
This chapter page keeps the exact class, subject, chapter, question count, answer checking, explanations and follow-up chapters together, so students can revise from one focused URL instead of searching through the full book again.
Class 9 Physics MCQ Preparation: Turning Effects of Forces
This page supports Matric Part 1 practice in Physics.
At this stage, the main purpose is building the definitions, symbols, rules and study habits needed for later matric work. The questions available here should be
used with the current textbook and the instructions issued by the learner's school or examination board.
What Physics MCQs can test
In Physics, objective questions commonly draw on definitions, physical quantities, SI units, laws, graphs, diagrams, formulas and the interpretation of numerical situations.
A useful answer is based on the exact wording and concept, not simply on recognising a familiar option.
For this subject, learners should write the known quantities and units before choosing a formula, and distinguish a law from the example used to demonstrate it.
Turning Effects of Forces: what to focus on
Relationships between physical quantities, direction, units, laws, graphs and the conditions under which an equation applies.
Sketch a simple situation or graph for difficult questions and check whether the selected option agrees with both the formula and the physical meaning.
Common mistakes for Class 9 learners
In this subject, frequent errors include mixing scalar and vector quantities, overlooking units, reversing cause and effect, or choosing a familiar formula without checking its conditions.
Separate new terms that look similar and connect every formula, rule or definition with at least one textbook example. When the page marks an answer as incorrect, the next step should be to identify
the mistaken idea and verify it, rather than memorising the displayed answer letter.
A practical revision routine
Read a small textbook section, answer a focused set of MCQs and correct the underlying idea before starting the next section. Before attempting the MCQs, review definitions, symbols, unit conversions, graph shapes, diagram labels and the meaning of each term in a formula.
Complete a manageable set without notes, check the result, and divide errors into missing knowledge,
misunderstood concepts and careless reading. Revise the appropriate section before repeating the chapter.
How to review Turning Effects of Forces after the quiz
List the questions you missed from Turning Effects of Forces and write the textbook heading
connected with each one. Explain the correct idea in your own words, then return later and answer a
fresh set. This gives the chapter page a clear purpose: finding specific weaknesses in
Physics rather than only collecting a score.
Accuracy and responsible use
Explanations are provided where they exist in the question bank, but educational databases can contain
incomplete or mistaken material. Confirm disputed answers with an authoritative textbook or teacher.
Ahmad Learning Hub provides a practice resource and does not claim that a question will appear in an
examination or that every available item represents an official board question.
Your privacy choices
Essential cookies keep login, security, and requested site features working. Optional Google Analytics loads only if you accept it. Third-party advertising is currently disabled. You can accept or reject optional cookies and change this choice later. Read our Privacy Policy.