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Saturday, 31 October

JEE Main 2025 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 7 April 2025, Shift 1, Physics Q29

Question 29 of 75 in this shift, Physics question 4 of 25, Section A.

A rod of length 5 L is bent right angle keeping one side length as 2 L. The position of the centre of mass of the system: (Consider L = 10 cm)

The figure, in words

L-shaped bent rod (hatched) in the x-y plane: vertical arm along the y-axis of length 3L and horizontal arm along the x-axis of length 2L, meeting at the origin.
  1. (1)2i^+3j^2\hat{i} + 3\hat{j}
  2. (2)4i^+9j^4\hat{i} + 9\hat{j}Official answer
  3. (3)3i^+7j^3\hat{i} + 7\hat{j}
  4. (4)5i^+8j^5\hat{i} + 8\hat{j}

Official answer

Option 2

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Center of Mass
Idea tested
COM of Bent Wires

Same topic in other shifts

All Center of Mass questions
  1. 2 Apr 2026, Shift 2 · Q28Two blocks of masses 2 kg and 1 kg respectively, are tied to the ends of a string which passes over a light frictionless pulley as shown…MediumSingle correctHas a figure
  2. 6 Apr 2026, Shift 1 · Q33The position of center of mass of three masses 2 kg, 3 kg and 15 kg placed with respect to mid point (pp) of normal bisector, as shown in…EasySingle correctHas a figure
  3. 6 Apr 2026, Shift 2 · Q32Two identical bodies A and B of equal masses have initial velocities v⃗1=4i^\vec{v}_1=4\hat{i} m/s and v⃗2=4j^\vec{v}_2=4\hat{j} m/s respectively.…MediumSingle correct
  4. 4 Apr 2024, Shift 2 · Q58In a system two particles of masses m1m_1= 3 kgkg and m2m_2 = 2 kgkg are placed at certain distance from each other. The particle of mass…EasyNumerical value
  5. 8 Apr 2024, Shift 1 · Q52A uniform thin metal plate of mass 10 kg with dimensions is shown. The ratio of xx and yy coordinates of center of mass of plate in…MediumNumerical valueHas a figure
  6. 1 Feb 2024, Shift 1 · Q52The identical spheres each of mass 2M are placed at the corners of a right angled triangle with mutually perpendicular sides equal to 4 m…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. 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.