Rotational Dynamics

 Chapter No:01

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Rotational Dynamics

In our day to day life we come across many interesting activity and we are curious about it, like how sports bike are able to turn at such great speed, how stunt is performed inside well of death (Maut ka kuwa), how top (bhawra) is able to rotate for so long without slipping? and many more.The fact behind all this is Rotational Dynamics.

Rotational stands for a object that is following a circular pattern.

Dynamics stands for  object in motion.

We can further Divide Rotational Dynamics into two parts

1) Circular Motion

2) Rotational Motion

Circular Motion : Motion of a particle which is along circumference of a circle  is known as circular motion.

Let us understand the concept in very simple way by visualization. In the given figure A, consider a circle of radius 'r' and point 'O' as centre. Let initially a particle is at position P and it displaces till Q. The distance from P to Q is called as linear displacement. At the same time, the position vector 'OP' and 'OQ' traces an angle  'θ'  between  P to Q at the centre. This is known as Angular displacement.

Fig A

A) Displacement

s : Linear Displacement

θ : Angular Displacement

Mathematically, 

                           

                                    S =  r θ 

Linear displacement = radius  X  Angular displacement

B) Velocity : If the particle takes time t to move from P to Q , then the velocity of the particle can be given by,

Mathematically,

B) Acceleration : It is the ratio of  change in velocity per unit time.

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As  Angular velocity and angular acceleration is a vector quantity , its direction is along the axis of rotation and it is given by right hand thumb rule.

Direction of angular velocity

│Uniform Circular Motion>>>│

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Related topics : Rotational dynamics     Uniform circular motion     Centripetal force  vehicle on horizontal curve road    well of death     banking of road     vertical circular motion    conical pendulum     kinetic energy of rotating body   moment of inertia   parallel axis theorem    perpendicular axis theorem   application of moment of inertia   Angular momentum   torque   conservation of angular momentum