someone pls explain to me circular motion in physics?

Question

i know the formula but that's about all I know!!! N I'm really confused. I missed those classes n I regret it a lot

what r the conditions of circular motion??

like.....*am i confused!!!* if the circle is big, does it effects velocity of the object? does the mass effect the velocity of the object?? n son on. i hope u got my point

there was a question in one of my test papers that said something like "If it was a big circle, would it effect its accleration? would it be slower or faster??" something like that.

Answer 1

Is there a specific topic in the broad category of circular motion which confuses you most?

Basically, circular motion is just that, motion in a circular path.
Sometimes the added constraint is added of "uniform" circular motion, consistent motion in a circular path (no angular acceleration,).

A KEY concept in circular motion is the idea that there is always a net force acting on the object.
We know from Newton's 2nd law that a net force causes acceleration....and that is just what happens.

Remember what acceleration is.....a change in velocity with respect to time. But you might think....if something is moving in uniform circular motion at a constant speed, it isn’t accelerating. But that is where you are wrong.
Velocity is a vector, and with it, it has both a magnitude AND a direction....a change in either one of these is a change in the velocity, which is in turn acceleration.
An object moving in a circle is constantly changing directions, it is constant accelerations since at any INSTANT in time, its velocity vector is pointed tangential (straight line outward, only touching the circle at a single point) to the object's path.

A net force (the "centripetal force") acts on the object to cause acceleration ("Centripetal acceleration").
The centripetal force / acceleration is always pointed inwards, towards the center of rotation.

* Just a side note to clarify what I am sure some people do not understand. There is no such thing as "centrifugal" force or acceleration which points outward...the net force (and only net force, as if more than one net force actually made any sense) is pointed inward...this is the centripetal force.

If, for some reason, the centripetal force were to stop being applied on the object (for example, the rope holding the object being swung in a circle breaks), the object will continue moving outward in a straight line in the direction it was moving when the force ceased, it would not continue a long its circular path.

Remember, although an object's "speed" might be constant in its path around the circle, is velocity is constant changing.
Speed is a scalar quantity, velocity is a vector.

Centripetal Force (F) is calculated as,
F = m * (v^2) / r
where m is the object's mass, v is the objects linear speed, and r is the radius away from the center the object is rotating.

Answer 2

A few things to remember:

1. Velocity is a vector, and has both a magnitude and direction.
2. Acceleration means that the velocity is changing (unless the acceleration is zero).
3. In circular motion, we can have a constant speed, but the direction of the object is still changing.

From 1 & 3, the velocity is changing for an object in circular motion, since the direction of motion is changing.
So from 2, there is an acceleration for an object moving in a circle, even if it's going a constant speed.

So there is an acceleration, and we also have a formula to calculate what it is (it's a = v^2 / r, as given in your text book or class notes).
Since there is acceleration, there must be a force (F=ma) producing that acceleration. Just multiply a by the mass m to get the force:
F = ma = m v^2 / r

That's about it, in a nutshell. Just remember that a change in direction means that the velocity is changing, so there must be acceleration. And remember those formulas for "a" and "F".

Answer 3

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Lesson 1: Motion Characteristics for Circular Motion

Speed and Velocity

Any moving object can be described using the kinematic concepts discussed in Unit 1 of The Physics Classroom. The motion of a moving object can be explained using either Newton's Laws (Unit 2 of The Physics Classroom) and vector principles (Unit 3 of The Physics Classroom) or by means of the Work-Energy Theorem (Unit 5 of The Physics Classroom). The same concepts and principles used to describe and explain the motion of an object can be used to describe and explain the parabolic motion of a projectile. In this unit, we will see that these same concepts and principles can also be used to describe and explain the motion of objects which either move in circles or can be approximated to be moving in circles. Kinematic concepts and motion principles will be applied to the motion of objects in circles and then extended to analyze the motion of such objects as roller coaster cars, a football player making a circular turn, and a planet orbiting the sun. We will see that the beauty and power of physics lies in the fact that a few simple concepts and principles can be used to explain the mechanics of the entire universe. Lesson 1 of this study will begin with the development of kinematic and dynamic ideas can be used to describe and explain the motion of objects in circles.

Answer 4

If you can understand a vector diagram, circular motion is a piece of piss. Draw a horizontal line and label the left hand end a. From a, draw another line the same length a small angle downwards from the first one.If you swing a weight on a string round in a circle, one moment it's going in the direction of the first line, and a moment later the tension in the string has pulled it so its direction has changed to the direction of the second line. To change the first vector in your diagram to the second one you have to add a short line to the right hand end at right angles to it. So centripetal acceleration is always at right angles to your direction of motion when you're travelling in a circle at constant speed.

Answer 5

Suppose that you tie a small rock to a rope and swing it in a circle around your head. You must apply a tension to the rope to keep the rock from flying off in a straight line. One formula for the force you apply to the rope is:
F = m v^2 / r, where F is the force in newtons, m is the mass of the object in kilograms, v is its velocity in meters per second, and r is the radius of the circle in meters (i.e., the length of the rope).

Answer 6

Newton's laws of motion and kinematic principles are applied to describe and explain the motion of objects moving in circles; specific applications are made to roller coasters and athletics. Newton's Universal Law of Gravitation is then presented and utilized to explain the circular and elliptical motion of planets and satellites.

See the link below