## Uniform Circular Motion – Class 11 | Chapter – 4 | Physics Short Notes Series PDF for NEET & JEE

Uniform Circular Motion: Uniform circular motion is a type of motion in which an object moves in a circle at a constant speed. In uniform circular motion, the velocity of the object is always tangent to the circle and the acceleration of the object is always directed towards the center of the circle. This acceleration is known as centripetal acceleration and is given by the following equation:

a = v2 / r

Where,

• v is the velocity of the object
• r is the radius of the circle.

In uniform circular motion, the speed of the object is constant but its velocity and direction are constantly changing. This means that the object is continuously accelerating, even though its speed is constant. The centripetal acceleration is necessary to keep the object moving in a circle and to maintain its constant speed.

Uniform circular motion is found in many everyday phenomena, such as the motion of the earth around the sun, the motion of a planet around its star, and the motion of a wheel rotating around its axis. It is also used in many technological applications, such as the design of roller coasters, flywheels, and turbines.

In conclusion, uniform circular motion is a fundamental concept in physics and engineering, and plays a critical role in our understanding of many physical and biological systems. It provides a useful way to describe and understand the behavior of objects moving in circles at constant speed and is essential for understanding a wide range of real-world phenomena.

## Formula of Uniform Circular Motion

There are several formulas that are commonly used to describe uniform circular motion. Here are some of the most important ones:

• Centripetal acceleration: a = v2 / r, where a is the centripetal acceleration, v is the velocity of the object, and r is the radius of the circle.
• Period of rotation: T = 2 * pi * r / v, where T is the period of rotation, v is the velocity of the object, and r is the radius of the circle.
• Centripetal force: F = m * a, where F is the centripetal force, m is the mass of the object, and a is the centripetal acceleration.
• Speed: v = 2 * pi * r / T, where v is the velocity of the object, T is the period of rotation, and r is the radius of the circle.
• Angular velocity: w = 2 * pi / T, where w is the angular velocity, and T is the period of rotation.
• Centripetal displacement: s = r * θ, where s is the centripetal displacement, r is the radius of the circle, and theta is the angle traveled by the object.

These formulas are useful in calculating and understanding the properties of uniform circular motion, such as speed, acceleration, force, and period. They are widely used in physics and engineering, and play a critical role in our understanding of many physical and biological systems.

## Characteristics of Uniform Circular Motion

Uniform circular motion is a type of motion in which an object moves in a circle at a constant speed. The following are some of the key characteristics of uniform circular motion:

• Constant speed: The object moves in a circle at a constant speed, meaning that its velocity magnitude is constant.
• Tangential velocity: The velocity of the object is always tangent to the circle, meaning that it is directed along the circumference of the circle.
• Centripetal acceleration: The object is constantly accelerating towards the center of the circle, even though its speed is constant. This acceleration is known as centripetal acceleration.
• Periodic motion: Uniform circular motion is a periodic motion, meaning that the object repeats its motion over and over again in equal time intervals.
• Radial direction: The centripetal acceleration is always directed towards the center of the circle.
• Dependence on radius: The period of rotation, the velocity, and the centripetal acceleration are all proportional to the radius of the circle.
• No net displacement: Although the object is moving in a circle, it does not experience any net displacement over time.

These characteristics of uniform circular motion provide a useful way to describe and understand the behavior of objects moving in circles at constant speed. They play a critical role in many real-world phenomena, such as the motion of planets and satellites, the operation of flywheels and turbines, and the design of roller coasters.

## Examples of Uniform Circular Motion

Here are a few examples of uniform circular motion:

• Planets in orbit: Planets moving in orbit around the sun are an example of uniform circular motion. They move at a constant speed along a circular path and experience centripetal acceleration towards the sun.
• CD players: CD players use a motor to spin a disk at a constant speed, producing uniform circular motion.
• Car wheels: When a car is driving in a circular path, such as when negotiating a bend in the road, the wheels experience uniform circular motion.
• Pendulum swings: A pendulum swinging back and forth in a regular pattern is an example of simple harmonic motion, but its path can be seen as a series of uniform circular motions about its pivot point.
• Rides at amusement parks: Many rides at amusement parks, such as the spinning tea cups or the tilt-a-whirl, use uniform circular motion to produce the sensation of spinning or rotating.

These are just a few examples of uniform circular motion that occur in our daily lives. This type of motion is an important concept in physics and engineering, and is used to understand a wide range of real-world phenomena and systems.

 JOIN OUR TELEGRAM CHANNELS Biology Quiz & Notes Physics Quiz & Notes Chemistry Quiz & Notes 