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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedHardMulti-step

JEE Main 27 August 2021, Shift 2, Physics Q5

Question 5 of 90 in this shift, Physics question 5 of 30, Section A.

The boxes of masses 2 kg and 8 kg are connected by a massless string passing over smooth pulleys. Calculate the time taken by box of mass 8 kg to strike the ground starting from rest. (use g=10 m/s2g=10\ \mathrm{m/s^2}) :

The figure, in words

A fixed pulley hangs from the ceiling; a string passes over it, one end going down to the right to a 2 kg box resting on the ground, the other end going down on the left around a movable pulley and back up to be fixed at the ceiling. An 8 kg box hangs from the axle of the movable pulley, with a gap of 20 cm marked between the bottom of the 8 kg box and the ground.
  1. (1)0.2 s0.2\ \mathrm{s}
  2. (2)0.34 s0.34\ \mathrm{s}
  3. (3)0.25 s0.25\ \mathrm{s}
  4. (4)0.4 s0.4\ \mathrm{s}Official answer

Official answer

Option 4

NTA final key.

Chapter
Laws of Motion
Topic
Newton's Laws of Motion
Idea tested
Constrained Motion

Same idea in other shifts

Asked 3× in all
  1. 26 Jul 2022, Shift 1 · Q31Three masses M=100M = 100 kg, m1=10m_1 = 10 kg and m2=20m_2 = 20 kg are arranged in a system as shown in figure. All the surfaces are frictionless…HardSingle correctHas a figure
  2. 26 Jun 2022, Shift 2 · Q32In the arrangement shown in figure a1,a2,a3a_1,a_2,a_3 and a4a_4 are the accelerations of masses m1,m2,m3m_1,m_2,m_3 and m4m_4 respectively. Which of…HardDiagram basedHas a figure

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.