Rest and motion ppt
- 1. REST AND MOTION • Motion is a combined property of an object under study and the observer. • Everything in the world is at rest or in motion. • There is no meaning of rest and motion without the viewer.
- 2. WHAT IS REST? • A body is said to be at rest it if does not change its position with respect to its surroundings. • For example, The passengers sitting in a moving bus are said to be at rest with respect to the driver of the same bus, because their positions do not change with respect to the driver.
- 3. WHAT IS MOTION? • A body is said to be in motion if it changes its position with respect to its surroundings. • For example, The passengers sitting in a moving bus are said to be in motion with respect to an observer standing outside the bus.
- 4. RELATIVE REST AND MOTION • Rest and motion are relative terms. • For example, a passenger sitting in a moving bus is at rest because he/she is not changing his/her position with respect to other passengers or objects in the bus. But to an observer outside the bus, the passengers and the objects inside the bus are in motion.
- 5. TYPES OF MOTION • Different objects move differently. Some objects move in a straight line, some move in a curved path and some move in other different way. • There are three types of motion: i. Translatory motion ii. Rotatory motion iii. Vibratory motion
- 6. TRANSLATORY MOTION • In translational motion, a body moves along a straight line. The line may be straight or curved. • For example, a car moving in a straight line is in translational motion and a train moving along a straight line also has translational motion.
- 7. TYPES OF TRANSLATORY MOTION • There are three types of translatory motion: i. Linear motion ii. Circular motion iii. Random motion • Linear motion: (if a body moves along a straight line) Example: aeroplane flying in a straight line. • Circular motion: (if a body moves in a circular path) Example: motion of earth around the sun. • Random motion: (the disordered or irregular motion of an object) • Example: motion of smoke or dust particles in the air.
- 8. ROTATORY MOTION • The spinning motion of a body about its axis is called its rotatory motion. • An axis is a line around which a body rotates. • For example, the motion of a wheel about its axis and that of a steering wheel are the examples of rotatory motion.
- 9. VIBRATORY MOTION • Vibratory motion is the back and forth (to and fro) motion of an object. • For example, a swing set. It vibrates back and forth as you swing it. Motion of the pendulum of a clock is also the example of vibratory motion.