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NEET 2021

Exam: NEET
Year: 2021
Subject: Physics
Chapter: Rotational Motion

NEET 2021 · Physics · Rotational Motion

A uniform rod of length 200cm and mass 500g is balanced on a wedge...

A uniform rod of length $200cm and mass$ 500g $is balanced on a wedge placed at$ 40cm $mark. A mass of$ 2kg $is suspended from the rod at$ 20cm $and another unknown mass$ m $is suspended from the rod at$ 160cm $mark as shown in the figure. Find the value of$ m $such that the rod is in equilibrium. \left( g = 10m{s}^{- 2}\right)$

A uniform rod of length 200cm and mass 500g is balanced on a wedge placed at 40cm mark. A mass of 2kg is suspended from

Options

A $\dfrac{1}{2}kg$
B $\dfrac{1}{3}kg$
C $\dfrac{1}{12}kg$
D $\dfrac{1}{6}kg$

Correct answer

C. $\dfrac{1}{12}kg$

Step-by-step solution

A uniform rod of length 200cm and mass 500g is balanced on a wedge placed at 40cm mark. A mass of 2kg is suspended from

Balancing torque about the wedge, we get

$2g \times 20 = 0 . 5g \times 60 + mg \times 120$

$⇒ 2 = 1 . 5 + 6m$

$⇒ m = \dfrac{0 . 5}{6} = \dfrac{1}{12}kg$

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