Define torque. Give its units.

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Jasmine Grover

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Torque is a measure of the ability of a force to rotate an object around an axis or a pivot. It is also known as the moment of force. Mathematically, torque (τ) is defined as the cross product of the force (F) and the distance (r) from the axis of rotation to the point of application of the force:

τ = r × F

where × denotes the vector cross product.

Torque

The units of torque depends on the units used for force and distance.

  • In the International System of Units (SI), the unit of force is the newton (N) and the unit of distance is the meter (m). Therefore, the unit of torque is the newton-meter (N⋅m).
  • In other systems of units, such as the British engineering system, the unit of force is the pound (lb) and the unit of distance is the foot (ft), so the unit of torque is the pound-foot (lb-ft).
  • The C.G.S unit of torque is dyne-cm.

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CBSE CLASS XII Related Questions

  • 1.
    Four independent waves are expressed as \[ (i)\; y_1=A_1\sin\omega t, \] \[ (ii)\; y_2=A_2\sin 2\omega t, \] \[ (iii)\; y_3=A_3\cos\omega t, \] \[ (iv)\; y_4=A_4\sin\left(\omega t+\frac{\pi}{3}\right) \] The interference between two of these waves is possible in

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    • 2.
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      • 3.
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          • 5 V
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        • 4.
          Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.


            • 5.
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                • 6.
                  If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

                    CBSE CLASS XII Previous Year Papers

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