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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedMediumCalculation

JEE Main 25 February 2021, Shift 2, Physics Q4

Question 4 of 90 in this shift, Physics question 4 of 30, Section A.

The point A moves with a uniform speed along the circumference of a circle of radius 0.36 m and covers 30∘30^{\circ} in 0.1 s. The perpendicular projection ‘P’ from ‘A’ on the diameter MN represents the simple harmonic motion of ‘P’. The restoration force per unit mass when P touches M will be :

The figure, in words

Circle with horizontal diameter MN (M at left, N at right), centre O. Point A on the circumference in the upper right; OA is drawn with angle 30° marked at O; the left half of the diameter is labelled 0.36 m; the arc near A is labelled 0.1 s. A vertical line from A meets the diameter at P, between O and N.
  1. (1)100 N
  2. (2)9.87 NOfficial answer
  3. (3)50 N
  4. (4)0.49 N

Official answer

Option 2

NTA final key.

Chapter
Oscillations
Topic
SHM Equations
Idea tested
SHM Definition and Force Law

Same idea in other shifts

Asked 5× in all
  1. 3 Apr 2025, Shift 1 · Q36Two blocks of masses m and M, (M>m)(M > m), are placed on a frictionless table as shown in figure. A massless spring with spring constant k…HardOtherHas a figure
  2. 9 Apr 2024, Shift 2 · Q57A particle of mass 0.500.50 kg executes simple harmonic motion under force F=−50 (Nm−1)xF=-50\ (Nm^{-1})x. The time period of oscillation is…EasyNumerical value
  3. 10 Apr 2023, Shift 2 · Q51A rectangular block of mass 5 kg attached to a horizontal spiral spring executes simple harmonic motion of amplitude 1 m and time period…EasyNumerical value
  4. 18 Mar 2021, Shift 2 · Q12The function of time representing a simple harmonic motion with a period of πω\frac{\pi}{\omega} is :MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.