NEET Physics: torque Practice Questions
14 free multiple-choice questions on torque (Rotational Motion) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. A larger distance (r) between the point of application of the force and the pivot point results in a larger torque, assuming the force remains constant. This is because:
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Correct answer: C — Torque is directly proportional to the product of r and F.
Since τ= rF, torque is directly proportional to the distance r when the force F is constant.
Q2. If a force is applied at a distance 'r' from the axis of rotation, the magnitude of the torque produced is proportional to which of the following factors?
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Correct answer: A — The distance 'r'
Torque (τ) is calculated as τ= rFsin θ. Therefore, the magnitude of torque is directly proportional to the distance r and the component of the force perpendicular to the radius.
Q3. When the force applied to a lever is parallel to the lever arm, what is the resulting torque produced?
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Correct answer: C — Zero torque
Torque is calculated using the perpendicular component of the force (Fsin θ). If the force is applied parallel to the lever arm (θ= 0° or 180°), sin θ= 0, resulting in zero torque.
Q4. The direction of the torque is determined by the direction of the force and the direction of the lever arm. This relationship is governed by the cross product, resulting in a vector quantity.
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Correct answer: B — Vector quantity
Torque is a vector quantity, meaning it has both magnitude and direction, determined by the cross product of the position vector and the force vector.
Q5. A force F is applied to a lever at a distance r from the pivot. If the force is applied perpendicular to the lever, the torque produced is given by the product of which two quantities?
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Correct answer: A — F and r
Torque (τ) is calculated as the product of the perpendicular component of the force (F_⊥) and the perpendicular distance (r) from the pivot, i.e., τ= F_⊥ · r. When the force is perpendicular (θ= 90°), sin θ= 1, so τ= F · r.
Q6. If the magnitude of the applied torque is doubled while keeping the distance from the pivot constant, how does the angular acceleration change?
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Correct answer: D — It is doubled
Torque is related to angular acceleration (τ= Iα). If torque is doubled and the moment of inertia (I) remains constant, the angular acceleration (α) must also be doubled.
Q7. Torque is calculated as the product of the magnitude of the force and the perpendicular distance from the axis of rotation to the line of action of the force. This perpendicular distance is known as:
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Correct answer: A — Moment arm
The perpendicular distance between the line of action of the force and the axis of rotation is called the moment arm or the lever arm, which is the distance 'r' in the torque formula.
Q8. The SI unit of torque is equivalent to which pair of units?
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Correct answer: D — Newton-meter and Newton
Torque is calculated as Force × Perpendicular distance (N · m). Since 1 Joule = 1 N · m, the SI unit for torque is Newton-meter (N·m).
Q9. Rotational equilibrium occurs when the net external torque acting on the body is zero. This means:
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Correct answer: C — The net rotational effect is zero.
Rotational equilibrium requires that the sum of all torques acting on the object must be zero (Στ= 0).
Q10. What is the SI unit of torque?
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Correct answer: A — Joule
Torque is the rotational equivalent of force and is measured in Newton-meter (N·m), which is equivalent to Joule (J) in energy context, but N·m is the standard unit for torque.
Q11. If a force is applied at a right angle to the radius vector, the angle (θ) between the force and the radius is:
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Correct answer: D — 90°
When the force is applied perpendicular to the radius, the angle θ between the force and the radius is 90°. In this case, sin(90°) = 1, so τ= rF.
Q12. If a force is applied perpendicular to the radius vector, what is the magnitude of the torque produced?
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Correct answer: A — rFsin 90°
Torque (τ) is calculated as rFsin θ. When the force is perpendicular to the radius (90°), sin 90° = 1, so τ= rF.
Q13. Torque (τ) is defined as the product of the force (F) and the perpendicular distance (r) from the pivot point. If the force is applied perpendicular to the lever arm, the formula simplifies to:
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Correct answer: D — τ= F · r
The definition of torque is τ= rFsin θ. When the force is perpendicular (θ=90°, sin 90°=1), the formula simplifies to τ= rF.
Q14. If a force of 5 N is applied at a distance of 0.5 m from a pivot, what is the magnitude of the torque produced?
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Correct answer: A — 1.0 N·m
Torque τ= rF = (0.5 m) × (5 N) = 2.5 N·m.
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