6 Questions
What is the main difference between circular motion and rotation?
Circular motion involves every particle in the object moving in a circular path around a point outside the object, while rotation involves motion around an axis passing through the object.
Why is circular motion considered as an accelerated motion?
Circular motion is accelerated because the direction of velocity changes at every instant.
What makes circular motion a periodic motion?
Circular motion is periodic because the particle repeats its path along the same trajectory.
What quantities are used to describe circular motion, analogous to displacement and velocity in translational motion?
Angular displacement (θ), angular velocity (ω), and angular acceleration (α) are used to describe circular motion.
How is tangential velocity related to angular velocity in circular motion?
Tangential velocity (v) is equal to the angular velocity (ω) multiplied by the radius (r).
What is the direction of angular velocity in circular motion?
The direction of angular velocity is always along the axis of rotation, determined by the right-hand thumb rule.
Study Notes
Rotational Dynamics
- Circular motion is an essential part of daily life, and we come across revolving or rotating objects every day.
Characteristics of Circular Motion
- It is an accelerated motion because the direction of velocity changes at every instant.
- It is a periodic motion because the particle repeats its path along the same trajectory.
Kinematics of Circular Motion
- Angular displacement (θ), angular velocity (ω), and angular acceleration (α) are used to describe circular motion.
- These quantities are analogous to displacement, velocity, and acceleration used in translational motion.
Angular Velocity and Acceleration
- The direction of ω is always along the axis of rotation and is given by the right-hand thumb rule.
- If α is constant in magnitude, but always perpendicular to ω, it will change the direction of ω and the plane of rotation.
Centripetal and Centrifugal Forces
- Centripetal force (CPF) is responsible for circular motion and is given by FCPF = (m × v^2) / r.
- Centrifugal force is a non-real force, but it can be measured and recorded by a force-measuring instrument.
- Centrifugal force is greater than the resultant force towards the centre when an object is accelerating from rest to a uniform speed.
Test your knowledge on rotational dynamics, mechanical properties of fluids, kinetic theory of gases, thermodynamics, and other key topics covered in class 12 Physics. From oscillations to semiconductor devices, this quiz covers various chapters of physics.
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