Learn

Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceDiagram basedMediumMulti-step

JEE Main 2 September 2020, Shift 1, Physics Q4

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

A bead of mass mm stays at point P(a,b)P(a, b) on a wire bent in the shape of a parabola y=4Cx2y=4Cx^{2} and rotating with angular speed ω\omega (see figure). The value of ω\omega is (neglect friction) :

The figure, in words

Parabola y=4Cx^2 opening upward about the y-axis (rotation axis, angular speed omega); bead at point P(a,b) on the right branch with dashed projections to the axes; origin O.
  1. (1)22gC2\sqrt{2gC}Official answer
  2. (2)2gC\sqrt{\frac{2g}{C}}
  3. (3)2gCab\sqrt{\frac{2gC}{ab}}
  4. (4)2gC2\sqrt{gC}

Official answer

Option 1

NTA final key (Sep 2020).

Chapter
Laws of Motion
Topic
Circular Motion
Idea tested
Bead on a Rotating Hoop

Same topic in other shifts

All Circular Motion questions
  1. 2 Apr 2026, Shift 1 · Q31A particle is rotating in a circular path and at any instant its motion can be described as θ=5t440−t33\theta=\frac{5t^4}{40}-\frac{t^3}{3}. The…EasySingle correct
  2. 5 Apr 2026, Shift 2 · Q30A wheel initially at rest is subjected to a uniform angular acceleration about its axis. In the first 2 s it rotates through an angle…EasySingle correct
  3. 8 Apr 2026, Shift 2 · Q28A car moving with a speed of 54 km/h takes a turn of radius 20 m. A simple pendulum is suspended from the ceiling of the car. Determine…EasySingle correct
  4. 5 Apr 2024, Shift 2 · Q32A man carrying a monkey on his shoulder does cycling smoothly on a circular track of radius 9 m and completes 120 resolutions in 3…EasySingle correct
  5. 8 Apr 2024, Shift 1 · Q32A clock has 75 cm, 60 cm long second hand and minute hand respectively. In 30 minutes duration the tip of second hand will travel xx…EasySingle correct
  6. 8 Apr 2024, Shift 2 · Q52A circular table is rotating with an angular velocity of ω\omega rad/s about its axis (see figure). There is a smooth groove along a…HardNumerical valueHas 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.