When the motion of a body follows a circular path around a fixed point, it is known as circular motion. Here, uniform circular motion is a particular kind of circular motion where the motion of the body follows a circular path at a constant/uniform speed. The body has a fixed central position and so remains at an equal distance from it at any known point.
When an object moves around in circular motion, there are many distinguishing factors to consider.
Explanation through an Example
You have a ball attached to a string, and you move it uniformly over a circular motion; then, two interesting observations can be made.
The speed of the ball remains constant, tracing the circle over a fixed center point.
The ball remains in motion changing its direction constantly. As such, one can opt to stay on a circular path; the ball must change its direction in a constant manner.
We can gain an important observation from the 2nd point. According to Newton’s first law, there will be no acceleration without a net force. As such, there must be a force entangled with the circular motion. Nevertheless, for a circular motion to happen, the object must be acted by a net force, thereby resulting in the change of direction otherwise known as centripetal force.
Imagine that your friend has been kidnapped by aliens, and they have kept him in an object moving in a circular motion. You will be able to save him, only after understanding the mechanism. This page will help you with the basics of circular motion.
From the above-mentioned theory, as long as your friend is in the field of circular motion, it will continue to follow the circular path. The moment the attachment breaks or you let go, the centripetal force stops acting, and your friend will be detached from the object. Then it will be easier for you to rescue your friend.
Types of Circular Motion
There are two kinds of circular motion that can act upon a body in motion:
Uniform circular motion or UCM,
Non-uniform circular motion
In the case of uniform circular motion, the angular speed & acceleration remains constant, whereas the velocity differs. However, in a non-uniform circular motion, both the angular speed and velocity change.
Uniform Circular Motion Formula
Consider a particle moving in a circle. It will have some acceleration acting at the center. This makes it move around the center position. As acceleration is perpendicular to the velocity, it only changes the direction of velocity, and the magnitude remains unchanged. This is the reason the motion is called uniform circular motion. This is otherwise called centripetal acceleration, and the force that acts towards the center is known as centripetal force.
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So, the centripetal force is the force acting on a body over a circular path. This points toward the center of the body in motion.
Considering the uniform circular motion, the acceleration is:
\[ ar = v^{2}r = \omega ^{2} r\]
where,
a=acceleration, r=radius, v=velocity of the object, ω=angular speed
If the mass of the particle is m, from the 2nd law of motion, you can find that:
\[ F = ma \]
\[Mv^{2}r = m\omega ^{2}r\]
So, if a particle moves in a uniform circular motion:
Its speed is constant
Velocity changes at every instant
No tangential acceleration acts on the body
Radial (centripetal) acceleration = \[ \omega ^{2}r \]
v=ωr
In the case of non-uniform circular motion, the tangential acceleration increases/decreases resulting in the acceleration to be the sum of tangential and radial acceleration.
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Uniform Circular Motion Examples
Below is the following example of uniform circular motion:
An example of uniform circular motion is the motion of artificial satellites around the earth. The satellites stay in the circular orbit around the earth due to gravitational force from the earth.
around the nucleus the motion of electrons. The perpendicular movement to the uniform magnetic field of electrons.
The blade of windmills motion.
With a circular dial, the tip of the second hand of a watch shows uniform circular motion.
A rope tied to the stone and being swung in a circular motion.
A curve in a road, a car turning through.
A gear-train inside turning a gear.
Clock hand motion.
Bicycle wheels of motion.
What is the concept of Uniform Circular Motion?
Uniform circular motion will always be used to describe the magnitude of the velocity. The direction of velocity will change at a constant rate from every place. The object's route will be in the shape of a circle, which represents it. The object will be completed after making multiple journeys around the path in the same length of time at the same spot.
The word circular refers to mobility along a curved path. Circular uniform motion is defined as an item moving along a circular path while covering the same distance along the circumference in the same time interval. The speed remains constant in such continually shifting motions.
The tangential speed will be constant at all points along the circumference in a uniform circular motion. The tangential velocity vector is tangent at all points around the circumference. As a result, the acceleration vector always points towards the center of the circle produced by the object's motion. Because it is at a given radius from a central point, or as a centripetal acceleration, or as a radical acceleration, which indicates that it is central seeking.
What are the learning objectives for Uniform Circular Motion?
You will be able to understand the following by the end of this section:
Of an object moving on a circular path solution for the centripetal acceleration.
Of a particle executing circular motion using the equations of circular motion to find the velocity, speed, and acceleration positioning.
Resulting from non-uniform circular motion explaining the differences between tangential acceleration and centripetal acceleration.
Find the total acceleration vector and evaluate tangential and centripetal equations in a non-uniform circular motion.
A specific type of motion in which an object travels in a circle with a constant speed at a particular time given is known as uniform circular motion. Some examples are a propeller spinning at a constant rate at any point is executing the circular uniform motion, the hour's hand, and the second minute of a watch. To watch all this we must know how to analyze the motion in terms of vectors at a particular period. Although the rotation rate is constant, remarkably, points on these rotating objects are accelerating.
FAQs on Uniform Circular Motion
1. What are three Examples of Circular Motion.
Further, here are some circular motion examples with pictures:
An artificial satellite that rotates around the Earth at a constant height,
A car when it turns to a curve in a race track,
An electron that moves perpendicular to a uniform magnetic field
Now, the object’s velocity vector constantly changes in direction and leads the moving object to be under acceleration by centripetal force. Also, without this acceleration, the object moves in a straight line as per Newton’s laws of motion.
Further, some common circular motion examples are:
Helicopter blades
Athlete running in a circular path
A stone tied to a string and rotated
Merry-go-round
Revolution of earth
Spinning top
Fan rotating
Wheel of bicycle
2. Write any Four Examples of Uniform Circular Motion.
Following are the four uniform circular motion examples:
The motion of artificial satellites around the earth. Here, the gravitational force inside the earth makes the satellite stay in a circular orbit.
Tip of 2nd hand of a watch with circular dial
The motion of blades of the windmill
The motion of electrons around the nucleus
The motion of a particle moving at a constant speed in or on a circle is called uniform circular motion. For example, car racing on a circular track, revolution, or rotation of the earth.
3. State the Important Properties of Uniform Circular Motion.
In a circular motion, there is a change in direction so that the body remains in acceleration.
Here the speed of the body remains in constant
The force which brings about uniform circular motion is the centripetal force which acts towards the center
This is a periodic motion with a definite frequency and period
The particle’s speed remains constant but velocity changes
It is an accelerated motion
Work done per periodic in uniform circular motion is zero.
4. What is the Difference between Uniform Linear Motion & Circular Motion?
Uniform Linear Motion
An object is in uniform linear motion if it travels in a straight-line covering equal length in equal time-interval.
There is no change in direction
Here, the velocity and speed remains constant
Acceleration is zero.
Example: A car moving forward at a speed of 50km/h towards the South direction.
Uniform Circular Motion
When a body moves in a circular path with a uniform speed
Here, the motion is in uniform acceleration
Speed remains constant, however the direction of motion changes
Example: An Athlete running in a circular path.
5. Give some Applications of Uniform Circular Motion.
Some real-life and everyday applications of uniform circular motion are:
Movements of minute hands of the clock.
Movement of blades of the fan.
In most amusement parks, we see giant wheels, merry go round, etc.
Revolution of planets around the sun.
Satellites orbiting the earth or heavenly bodies.
On a circular track athlete running.
Windmill movement.
Circularly walking in a park at a particular speed and at a given point of time.