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Friday, 9 October

JEE Main 2025 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 3 April 2025, Shift 2, Physics Q31

Question 31 of 75 in this shift, Physics question 6 of 25, Section A.

A block of mass 1 kg, moving along xx with speed vi=10v_i = 10 m/s enters a rough region ranging from x=0.1x = 0.1 m to x=1.9x = 1.9 m. The retarding force acting on the block in this range is Fr=−kx\mathrm{F_r} = -kx N, with k=10\mathrm{k} = 10 N/m. Then the final speed of the block as it crosses rough region is.
  1. (1)10 m/s
  2. (2)8 m/sOfficial answer
  3. (3)6 m/s
  4. (4)4 m/s

Official answer

Option 2

NTA final key.

Chapter
Work, Energy and Power
Topic
Work and Kinetic Energy
Idea tested
Work by Variable Force

Same idea in other shifts

Asked 3× in all
  1. 9 Apr 2024, Shift 2 · Q51A force (3x2+2x−5)(3x^2+2x-5) N displaces a body from x=2x=2 m to x=4x=4 m. Work done by this force is ___________ J.EasyNumerical value
  2. 11 Apr 2023, Shift 1 · Q59A force F⃗=(2+3x)i^\vec{F} = (2 + 3x)\hat{i} acts on a particle in the xx direction where F is in newton and xx is in meter. The work done by…EasyNumerical value

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 42 of the 174 JEE Main shifts held from 2017 to 2026.