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JEE Main 2023 (30 Jan, Shift 2) · Equilibrium, Third Law & Frames

Equilibrium, Third Law & Frames question from JEE Main 2023 (30 Jan, Shift 2)

Q11JEE Main 2023 · 30 JAN · SHIFT 2Easy

Equilibrium, Third Law & Frames

A block of 3 kg\sqrt{3}\text{ kg} is attached to a string whose other end is attached to the wall. An unknown force FF is applied so that the string makes an angle of 30∘30^\circ with the wall. The tension TT is: (Given g=10 m s−2g = 10\text{ m s}^{-2})

Figure

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Answer: (d)

  1. At the junction, the vertical component of TT balances the weight (the string is at 30∘30^\circ to the vertical wall).
  2. Tcos⁡30∘=mg=3×10T\cos 30^\circ = mg = \sqrt{3} \times 10
  3. T⋅32=103⇒T=20 NT \cdot \frac{\sqrt{3}}{2} = 10\sqrt{3} \Rightarrow T = 20\text{ N}
  4. So the answer is (d) 20 N.
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