Torque & Rotational Equilibrium questions with solutions

Showing 1–10 of 40 questions

• MCQmediumRotational MotionTorque & Rotational Equilibrium

  As shown in the figure, a uniform rod can be rotated freely about point A in the vertical plane. When a vertical upward force F lifts up the rod slowly from position shown, which of the following statements is correct till the rod becomes horizontal ?

  

  Options

  • Option A

    The pulling force is unchanged, its moment of force increases.

  • Option B

    The pulling force is unchanged, its moment of force decreases.

  • Option C

    The pulling force increases, its moment of force decreases.

  • Option D

    The pulling force decreases, its moment of force decreases.

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  JEE MainsNEET

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• IntegermediumRotational MotionTorque & Rotational Equilibrium

  A thin solid disc of mass 1 kg rotates about a diameter at 1800 rpm. A constant external torque 25π N·m acts for 40 s, increasing its speed to 2100 rpm. Find the diameter of the disc in metres.

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  JEE Mains 2025 8 April Evening Shift (Shift 2)

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• NumericmediumRotational MotionTorque & Rotational Equilibrium

  A particle of mass 1 kg is acted on by $\vec{F}$ = -k(x î + y ĵ), where k = 1 kg s⁻². At t = 0, $\vec{r}$ = (î/√2 + √2 ĵ) m and $\vec{v}$ = (-√2 î + √2 ĵ + (2/π)k̂) m s⁻¹. Ignore gravity. When z = 0.5 m, find x vᵧ - y vₓ in m² s⁻¹.

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  JEE Advanced 2022

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• MCQmediumRotational MotionTorque & Rotational Equilibrium

  A heavy iron bar of weight 12 kg is having its one end on the ground and the other on the shoulder of a man. The rod makes an angle 60° with the horizontal, the weight experienced by the man is :

  Options

  • Option A

    6 kg

  • Option B

    12 kg

  • Option C

    3 kg

  • Option D

    6√3 kg

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  JEE Mains 2024 27 Jan Evening Shift

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• MCQmediumRotational MotionTorque & Rotational Equilibrium

  Which statements are correct? (I) Centre of mass always coincides with centre of gravity. (II) The centre of mass is the point where total gravitational torque on a body is zero. (III) A couple causes both translation and rotation. (IV) Mechanical advantage >1 lets a small effort lift a large load.

  Options

  • Option A

    (II) and (IV)

  • Option B

    (I) and (II)

  • Option C

    (II) and (III)

  • Option D

    (III) and (IV)

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  NEET 2017

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• IntegermediumRotational MotionTorque & Rotational Equilibrium

  A force -P k̂ acts at the origin. The torque about the point (2, -3) is P(aî + bĵ). If a/b = x/2, find x.

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  JEE Mains10 April 2023Shift 2Evening Shift

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• MCQmediumRotational MotionTorque & Rotational Equilibrium

  A uniform disc of mass 2 kg and radius 1 m is acted upon by torque τ(t)=5t²-8t N m. The disc starts from rest. Find the power delivered by the torque at t=1 s.

  Options

  • Option A

    5 W

  • Option B

    3 W

  • Option C

    7 W

  • Option D

    9 W

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  JEE Mains 2025 23 Jan Evening Shift

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• MCQmediumRotational MotionTorque & Rotational Equilibrium

  A solid cone hangs from a frictionless pivot at the origin O, as shown. If î, ĵ and k̂ are unit vectors, and a, b, and c are positive constants, which of the following forces F applied to the rim of the cone at a point P results in a torque τ on the cone with a negative component τz?

  

  Options

  • Option A

    $\vec{F}$ = a k̂, P = (0, b, -c)

  • Option B

    $\vec{F}$ = -a k̂, P = (0, -b, -c)

  • Option C

    $\vec{F}$ = a ĵ, P = (-b, 0, -c)

  • Option D

    None of these

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• MCQeasyRotational MotionTorque & Rotational Equilibrium

  If $\vec{F}$ acts at position vector $\vec{r}$ , with torque $\vec{\tau}$ about the origin, which relations are always correct?

  Options

  • Option A

    $\vec{r}.\vec{\tau}$≠0 and $\vec{F}.\vec{\tau}$=0

  • Option B

    $\vec{r}.\vec{\tau}$>0 and $\vec{F}.\vec{\tau}$<0

  • Option C

    $\vec{r}.\vec{\tau}$=0 and $\vec{F}.\vec{\tau}$=0

  • Option D

    $\vec{r}.\vec{\tau}$=0 and $\vec{F}.\vec{\tau}$≠0

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  AIPMT Screening 2009NEET

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• MCQmediumRotational MotionTorque & Rotational Equilibrium

  On a disc of radius R a concentric circle of radius R/2 is drawn. The disc is free to rotate about a frictionless axis through its centre and perpendicular to plane of the disc. All the three forces (in plane of the disc) shown in figure are act tangentially to their respective circular periphering. The magnitude of the net torque (about centre of disc) acting on the disc is:-

  

  Options

  • Option A

    1.9FR

  • Option B

    2.3FR

  • Option C

    2.5FR

  • Option D

    1.5FR

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