# The Dynamics of Circular Motion, to Know in Physics

The dynamics of circular motion involves the study of the forces acting on the object in a circular motion, and how these forces affect its motion. Circular motion is the movement of an object around a fixed point or axis in a circular path. The object continually changes direction, but its distance from the fixed point remains constant.

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## The dynamics of circular motion

The dynamics of circular motion involves the study of the forces acting on the object in a circular motion, and how these forces affect its motion. Circular motion is the movement of an object around a fixed point or axis in a circular path. The object continually changes direction, but its distance from the fixed point remains constant.

Examples of circular motion include the rotation of a planet around the sun, the motion of a car around a racetrack, or the motion of a ball on a string being swung in the air.

The key concepts related to the dynamics of circular motion include centripetal force, centrifugal force, angular velocity, tangential velocity, centripetal acceleration, conservation of angular momentum etc.

## The dynamics of circular motion: Centripetal Force

In a circular motion, an object moves along a curved path, but it always experiences a force pointing towards the centre of the circle. This force is called the centripetal force, which is responsible for keeping the object in its circular path. The centripetal force is always perpendicular to the object’s tangential velocity, which is the component of the object’s velocity that is tangent to the circular path.

In the case of a horizontal circular path, this force can be provided by the force of friction between the object and the surface it is moving on. In the case of a vertical circular path, this force can be provided by the force of gravity acting on the object.

In addition to centripetal force, other forces can also affect the motion of objects in circular paths. For example, air resistance can cause a decrease in the speed of an object in a circular motion, while external forces such as a gust of wind can cause the object to deviate from its circular path. The centripetal force can be given by the formula such as;

Fc = mv2/r

Where,

• Fc is the centripetal force.
• m is the mass of the object.
• v is the velocity of the object.
• r is the radius of the circular path.

## The dynamics of circular motion: Centrifugal Force

Centrifugal force is an apparent force that appears to act on the object in the opposite direction to the centripetal force. However, it is not a real force but a result of the object’s inertia. The centrifugal force is equal in magnitude and opposite in direction to the centripetal force, as given by Newton’s Third Law.

The magnitude of centrifugal force can be calculated using the following equation:

Fcf = mv2/r

where,

• Fcf is the centrifugal force.
• m is the mass of the object.
• v is the velocity of the object.
• r is the radius of the circular path.

This equation tells us that the magnitude of centrifugal force is directly proportional to the mass of the object, the square of its velocity, and inversely proportional to the radius of the circle.

It is a fact that while centrifugal force is not a real force, it can have real effects. For example, if a car is moving too fast around a curve, the centrifugal force may cause it to skid off the road.

## The dynamics of circular motion: Angular Velocity

The rate at which an object in circular motion rotates around its axis is called its angular velocity. It is measured in radians per second (rad/s). The angular velocity of an object is related to its linear velocity and the radius of its circular path. The formula of angular velocity can be;

ω = v/r

where,

• ω is the angular velocity,
• v is the linear velocity, and
• r is the radius of the circular path.

## The dynamics of circular motion: Tangential Velocity

The linear velocity of an object in circular motion tangent to its circular path is called its tangential velocity. It is can be given by the formula,

vt = rω

where,

• vt is the tangential velocity,
• r is the radius of the circular path, and
• ω is the angular velocity.

## The dynamics of circular motion: Centripetal acceleration

The acceleration of an object in a circular motion towards the centre of its circular path is called centripetal acceleration. It can be given by the formula:

ac = v2/r = rω2

where,

• ac is the centripetal acceleration.
• v is the linear velocity.
•  r is the radius of the circular path.
• ω is the angular velocity.

## The dynamics of circular motion: Conservation of Angular Momentum

The angular momentum of an object in circular motion remains constant unless acted upon by an external torque. The formula gives the angular momentum of an object as such,

L = Iω

Where

• L is the angular momentum,
•  I is the moment of inertia of the object, and
•  ω is the angular velocity.

## FAQs of Dynamics of Circular Motion

1. What is circular motion?

Ans: Circular motion is the movement of an object along a circular path or trajectory.

2. What is the centripetal force?

Ans: The centripetal force is the force that is directed towards the centre of the circular path and is responsible for keeping an object in a circular motion.

3. What is the relationship between velocity and centripetal force in circular motion?

Ans: The velocity of an object in circular motion is directly proportional to the centripetal force acting on the object. This means that the faster an object is moving in a circular path, the greater the centripetal force required to keep it moving in that path.

4. What is the difference between uniform circular motion and non-uniform circular motion?

Ans: Uniform circular motion is the motion of an object moving at a constant speed along a circular path, while non-uniform circular motion is the motion of an object that is changing its speed or direction as it moves along a circular path.

5. What is the relationship between radius and centripetal force in circular motion?

Ans: The centripetal force required to keep an object moving in a circular path is directly proportional to the radius of the circular path. This means that the greater the radius of the circular path, the greater the centripetal force required to keep the object moving in that path.

6. What is the relationship between mass and centripetal force in circular motion?

Ans: The centripetal force required to keep an object moving in a circular path is directly proportional to the mass of the object. This means that the greater the mass of the object, the greater the centripetal force required to keep it moving in that path.

7. What is the relationship between frequency and period in circular motion?

Ans: Frequency and period are inversely proportional in a circular motion. This means that the higher the frequency of an object’s motion, the shorter the period of its motion, and vice versa.

8. What is the difference between tangential speed and angular speed in circular motion?

Ans: Tangential speed is the linear speed of an object moving along a circular path, while angular speed is the rate at which the object rotates around the centre of the circular path. Tangential speed is measured in meters per second, while angular speed is measured in radians per second.

## Conclusion,

The dynamics of circular motion involves the study of forces and accelerations acting on an object moving in a circular path, as well as the relationships between linear and angular velocities, and the conservation of angular momentum.