Define Rest
an object is at rest if it doesn’t change its position with respect to its surroundings and the passage of time.
Define Motion
an object is at motion if it changes its position with respect to its surroundings and the passage of time.
One dimensional motion
the motion of an object is said to be one dimensional if only one of the three coordinates specifying the position change with time.
Two Dimensional motion
the motion of an object is said to be two dimensional if only two coordinates out of the three specifying the position change with time.
Three Dimensional motion
The motion of an object is said to be three dimensional if all the three coordinates which specify the position of the obect change with time.
Distance
measure of the actual path traversed by a body between its initial and final position.
Displacement
Teh displacement of an object is the change in position of an object in a fixed direction. It is the shortest path measured in the direction from the initial point to the final point.
characteristics of displacement
-> displacement has the unit of length
-> displacement of an object can be (+) ve or (-)ve or zero
-> displacement is not dependent on the choice of origin
-> the actual distance travelled by an object is greater than or equal to the magnitude of the displacement.
Speed
speed is the rate of change of position of an object with time in any direction.
Uniform speed
an object is said to be moving in uniform speed if it travells equal distances in equal intervals of time.
Variable speed
an object covering unequal distances in equal intervals of time is traveling in variable speed
average speed
the total distance traveleed by an object by the total time taken to cover the distance.
Instantaneous speed
the speed of an object at a specific point of its path or at a particular instant of time.
Speedometer
instantaneous speed
Velocity
the rate of change of an object displacement with time and follows the parallelogram law of addition.
acceleration
acceleration is the rate of change of velocity of an object with time
position time graph: body at rest
position time graph: uniform speed
postion time graph : accelerated motion
position time graph: negative displacement
speed time graphs:
for a body thrown upwards
speed time graph:
body thrown downward
speed time graph: uniform velocity
speed time graph: constant acceleration
