Circular Motion

You must have seen a merry-go-round revolving in a circle on a fixed axis. Ever wondered about the concept behind it? Or the concept behind the revolution of planets around the sun? Behind the revolving fan above you? All these concepts revolve around only one topic–circular motion. The round motion of any object is known as circular motion. Have you ever experienced a revolving top? It also uses the same concept. 

Circular Motion

When an object revolves in a circular manner, it is known as circular motion. Famous examples of circular motion are toy tops revolving on earth, planets revolving around the sun, a cow moving around a fixed axis. Circular motion is classified into two types: 

1. Uniform circular motion: When an object revolves in a circular manner, its velocity is constant. This is termed uniform circular motion. 
2. Non-uniform circular motion: If an object is revolving in a circular manner and its velocity is not constant, it is known to be revolving in a non-uniform circular motion. 

Examples of Uniform Circular Motion

Famous examples of uniform circular motion are: 

• When a satellite revolves around the earth, the earth’s gravitational force attracts it towards it and forces it to revolve in a circular path. 
• The movement of electrons around the nucleus in the study of chemistry is an excellent example of uniform circular motion. 
• The movement of blades of windmills in a field. 
• The movement of the second hand, minute hand, and hour hand of the clock.

Circular Motion: Variables

1. Angular displacement: The presence of an angle subtended by the position vector at the centre of the circular path is called angular displacement. The formula of angular displacement is

Angular displacement (Δθ) = (ΔS/r)

where,

Δθ is the angular displacement

ΔS is the linear displacement

r is the radius, and the unit is the radian. 

2. Angular velocity: The rate of change of angular displacement in relation to the change of time is angular displacement. It is a vector quantity, and its SI unit is rad/s. The formula of angular velocity is.

Angular velocity (ω) = (Δθ/Δt)

where,

ω is the angular velocity

Δθ is the angular velocity

Δt is a change in time

To derive the relationship between angular velocity and linear velocity,

v=rw

3. Angular acceleration: The rate of change of angular velocity in relation to the change in time is called angular acceleration. The unit of angular acceleration is rad/s^2, and its dimensional unit is [T^-2]. The formula of angular acceleration is

Angular acceleration() = dwdt = d2dt2

Where,

is angular acceleration

The relationship between linear acceleration and angular acceleration is 

a = rα

where, 

r is the radius

a is the acceleration

α is the angular acceleration

Kinetics of Circular Motion

The kinetics of circular motion refers to the presence of a relation between different variables of an object that exhibits a circular motion. The equations for this type of motion are known as kinematical equations of circular motion. The three equations of circular motion are as follows:

(i) =0+t

(ii) =0t+12t2

(iii) 2=02+2

Where,

ω0 signifies the initial angular velocity

ω signifies the final angular velocity,

α signifies the angular acceleration

θ signifies the angular displacement 

t signifies time

Conclusion

This article covers relevant information on circular motion, including its definition, types of circular motion with examples, and the three variables of uniform circular motion. The final topic, the kinetics of circular motion, contains the formula to solve problems of circular motion.