Angular Kinetics of Human Movement

Prepared by:Hazrat Bilal Malakandi

DPT (IPM&R, KMU)

Moment of Inertia

• Angular analogue of mass.

• Formula --- I = mk2

• Units of moment of inertia consist of mass multiplied by units of length squared ( kg•m2)

Angular Momentum

• For linear motion: M = mv = I ω

L = mk2 • Factors that affect a angular momentum– Mass (m), distribution of mass with respect to the

axis or rotation (k) , angular velocity of the body ()

Angular Analogues of Newton’s Laws of Motion

Newton’s First Law: • A rotating body will maintain a state of

constant rotational motion unless acted on by an external torque.

Newton’s Second Law: • A net torque produces angular acceleration of

a body that is directly proportional to the magnitude of the torque, in the same direction as the torque, and inversely proportional to the body’s moment of inertia.

Newton’s Third Law: • For every torque exerted by one body on

another, there is an equal and opposite torque exerted by the second body on the first.

Centripetal Force

centripetal force is defined as a force whichkeeps a body moving with a uniform speedalong a circular path and is directed along theradius towards the centre.

• Fc = m ac

• Fc = mv2 / r

• Fc = mr 2

Angular acceleration

• Rate of change of angular velocity

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