Circular Motion
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| Figure 1: Ferris Wheel |
Circular motion is a motion of any object that moves in a circle, or making a circular path. Simple examples of this motion are:
1)The earth orbiting the Sun; the earth acts as the object
2) The person in a Ferris Wheel; the person acts as the object
3) Hammer throwing; the metal ball acts as the object
Before this we have learned linear motion and projectile motion from Chapter 2. So now, for your information, we are going to learn one more type of motion in Chapter 6 that is circular motion. This motion is of course not the same as the linear motion. If you could recall, linear motion is the motion in a straight line. If in linear motion , we have the term displacement, velocity and acceleration, so do the circular motion :) The names are also a bit different as you can see from the table below:
LINEAR MOTION
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CIRCULAR
MOTION
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Displacemenet
, s
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Angular
Displacement, θ
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Velocity,
v
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Angular
Velocity, ω
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Acceleration,
a
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Centripetal
Acceleration, α
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Angular displacement, θ
Angular displacement θ is actually an angle swept by an object when it moves in a circular motion. For example, the motion from A to B as shown in Figure 2 below. Measuring angles can also be in radians apart from degrees, and knowing that we can calculate how many radians covered by using the formula θ = s/r. Radian is the unit we use for circular motion. In the figure, you can see that, to turn through θ, you need to move a distance of s. This is how s is related to θ.
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| Figure 2: Angular Displacement |
Angular Velocity, ω
To describe how fast an object moving is circular motion, we will calculate the angle it turns through in a given time. It's θ / t and this what we call angular velocity ω. It is also called the angular frequency and the name of the symbol is 'omega'.
One thing you have to know here is that there is a relation between the linear velocity v and angular velocity ω and this is shown in the yellow box below. If we have an object positioned at maximum radius (object 2) , it will move with the higher speed compared to other object near the centre of the circle.(object 1).This is because of the radius dependency as long as their angular velocities are the same.
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| Figure 3: Linear speed vs Angular speed |
Mdm Ummi Atiah KMPk
~ May it Benefits You ➽đź’•
Tq madam❤️
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