Class 7 Physics Motion and Time Motion

Motion

Motion is a change in position of an object with respect to time.If the position of a body is not changing with respect to time, the body is said to be at rest, motionless, immobile or stationary.Any moving body is said to be in motion.Some types of motions are show below:

Motion is based on Frame of Reference.When a person standing outside the bus is considered as a reference, the bus is in motion. When a person sitting inside the bus is considered as a reference, the bus appears to be stationary.

Oscillatory Motion:

• An oscillatory motion is a motion where a body moves between two extreme positions.
• The center of these extreme positions is called mean position.
• Time taken to complete one oscillation is called Time Period.
• When an oscillatory motion repeats itself in equal intervals of time it is called Periodic Motion.
• All periodic motions could not be oscillatory, but all oscillatory motions are periodic in nature.

Examples of oscillatory motion pendulum, swings, object attached to a spring, etc.

Examples of periodic motion pendulum, revolution of earth on its axis, rotation of earth around sun etc.

Uniform and Non-Uniform Motion:An object having uniform motion travels equal distances in equal intervals of time and An object having non-uniform motion travels unequal distances in equal intervals of time.

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