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Saturday, 31 October

JEE Main 2022 · PhysicsMultiple choiceSingle correctHardMulti-step

JEE Main 26 July 2022, Shift 1, Physics Q31

Question 31 of 90 in this shift, Physics question 1 of 30, Section A.

Three 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 and strings are inextensible and weightless. The pulleys are also weightless and frictionless. A force F is applied on the system so that the mass m2m_2 moves upward with an acceleration of 2 ms−22\ \mathrm{ms^{-2}}. The value of F is : (Take g=10 ms−2g = 10\ \mathrm{ms^{-2}})

The figure, in words

Block labelled M = 100 kg rests on a flat surface; a smaller block labelled m1 = 10 kg sits on top of M near its right end. A string runs from m1 horizontally to a pulley at the top right corner of M, then down to a block labelled m2 = 20 kg hanging beside the right face of M. A horizontal arrow labelled F points right, toward the left face of M.
  1. (1)3360 N
  2. (2)3380 N
  3. (3)3120 NOfficial answer
  4. (4)3240 N

Official answer

Option 3

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 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
  2. 27 Aug 2021, Shift 2 · Q5The 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…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.