**Motion**: A body is to be in motion when its position changes continuously with respect to a stationary object taken as reference point.

**Uniform motion:** A body has a uniform motion if it travels equal distances in equal intervals of time, no matter how small these time intervals may be.

**Uniform speed:** A body has a uniform speed if it travels equal distance in equal intervals of time, no matter how small these time intervals may be.

**Circular motion:** When a body moves in a circle, then the motion of the body is defined as circular motion.

**Uniform circular motion**: Any body when moves in a circular path with uniform speed then its motion is known as **uniform circular motion**. When a body moves in circular path, then its direction of motion keeps changing continuously. A force is needed to produce circular motion. The force which is needed to make an object travel in a circular path is called centripetal force.

Diagram of uniform circular motion:

**Formula to calculate speed of a body in a uniform circular motion:**

A body takes one round of a circular path, then it travels a distance equal to its circumference,

circumference = 2`Pi`r where r is the radius of the circular path.

The speed of the body moving along circular path is given as,

v = `(2pir)/(t)`

where, `Pi = 22/7` , r = radius of the circular path, t = time taken for one round of circular path.

- Artificial satellites move under uniform circular motion around the earth. The force of the gravity of the earth keeps the satellite in circular orbit around it
- The moon moves in uniform circular motion around the earth.
- All the planets move in uniform circular motion around the sun.
- The tip of seconds' hand of a watch exhibits uniform circular motion on the circular dial of the watch.
- An athlete moving on a circular track with a constant speed exhibits uniform circular motion.
- A stoned tied to a thread and rotated in circular motion.

Try this out **Motion Equations** which i would like to share with you it may help you.

- Wheel of any vehicle moves along a circular path.
- Merry-go-around in full speed.
- Water pump in a garden which throws water in a circular motion
- An electron moving around its nucleus
- Amusement park rides
- An audio CD or disc runs in a player
- Moving fan
- Moving turbine
- Wind mill

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