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Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 27 June 2022, Shift 2, Physics Q34

Question 34 of 90 in this shift, Physics question 4 of 30, Section A.

One end of a massless spring of spring constant kk and natural length l0l_0 is fixed while the other end is connected to a small object of mass mm lying on a frictionless table. The spring remains horizontal on the table. If the object is made to rotate at an angular velocity ω\omega about an axis passing trough fixed end, then the elongation of the spring will be :
  1. (1)k−mω2l0mω2\frac{k - m\omega^{2}l_0}{m\omega^{2}}
  2. (2)mω2l0k+mω2\frac{m\omega^{2}l_0}{k + m\omega^{2}}
  3. (3)mω2l0k−mω2\frac{m\omega^{2}l_0}{k - m\omega^{2}}Official answer
  4. (4)k+mω2l0mω2\frac{k + m\omega^{2}l_0}{m\omega^{2}}

Official answer

Option 3

NTA final key.

Chapter
Laws of Motion
Topic
Circular Motion
Idea tested
Spring-Mass in Circular Motion

Same idea in other shifts

Asked 5× in all
  1. 6 Apr 2023, Shift 1 · Q48A small block of mass 100 g is tied to a spring of spring constant 7.5 N/m and length 20 cm. The other end of spring is fixed at a…MediumSingle correct
  2. 30 Jul 2022, Shift 2 · Q4A mass of 0.5 kg is attached to one end of a massless spring whose natural length is 1 m and spring constant is 800 N/m The other end of…MediumSingle correct
  3. 8 Jan 2020, Shift 1 · Q2A particle of mass m is fixed to one end of a light spring having force constant k and unstretched length ll. The other end is fixed. The…MediumSingle correct
  4. 9 Jan 2020, Shift 2 · Q6A spring mass system (mass mm, spring constant kk and natural length ll) rests in equilibrium on a horizontal disc. The free end of the…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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.