A body is said to be in motion, if it changes its position with respect to time. If not so, then body is said to be at rest. A racing car, flying aeroplane, flowing rivers, rolling ball are all in motion whereas, a standing bicycle, a tree, wall of room are at rest. To understand whether an object is moving or in rest, it is necessary to take a reference point. A reference point is a fixed point. A person sitting in the train understand that train is moving with reference of tree.
Motion in straight line
It is also known as rectilinear or just linear motion. If object travels from one point to another, then the length travelled is the distance travelled. If distance travelled is 30 km then magnitude of distance is 30 km.
- Displacement: Displacement is the shortest distance from initial to final position. Displacement and distance are two different terminologies. For example, if a car travels 50 km from point A to point B and returns at point A again, then distance travelled by car is A to B and B to A that is 50 km + 50 km. Therefore, total distance travelled is 100 km. In case of displacement, shortest distance between initial and final point will be 50 km. In short, displacement will be always less than or equal to distance travelled by the object. If initial and final position are same magnitude of displacement is zero, but magnitude of distance travelled will be non zero.
Uniform and Non-uniform motion
Uniform and Non uniform Motion
- If an object travels equal distance in equal time interval, then object is said to be in uniform motion. For example, a car travel 5 km in every 5 minutes then car is in uniform motion. Some other examples are motion of earth around the sun, moving of minute hand of clock, etc.
- If an object travels unequal distance in equal time interval then it is in nonuniform motion. For example, a car travels 2 km in first 5 minutes and 5 km in next 5 minutes, then car travel unequal distance in equal time interval. Therefore car is in non uniform motion. Some other example of non uniform motion are vehicle moving through crowd, bouncing of ball, etc.
Keywords: Uniform motion, Non uniform motion
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