Post on 10-May-2015
PHYSICS
MOTION
Some objects in our surrounding are moving with respect to the stationary ones. Based on that object or body in our surroundings, our environment can be classified as :-
• Stationary Objects ( in rest )
• Moving Objects ( in motion )
CONCEPT :-
Stationary body Moving body
A body is said to be in motion when it’s position changes continuously with respect to reference point (stationary object).
• E.g.:- hand of the clock are in motion.
Reference point :-
• When a car moves in front of a forest
• With respect to the trees car is moving.
• Trees – reference point
MOTION
Stationary object
Moving object
Reference Point
Scalar :
• Gives only magnitude
Vector :
• Give both magnitude and direction
Vector and Scalar
Displacement
Distance
e.g.
Scalar
Vector
Distance
•The length of actual path travelled by an object is known as Distance covered by the object.• It is a scalar quantity.
Displacement
•The shortest distance between the final and the initial point is called displacement.•Displacement is of scalar quantity
A body travels in uniform motion when it travels equal distance in equal interval of time.
A body travels in Non uniform motion when it travels unequal distance in equal interval of time.
Uniform and Non Uniform motion
Uniform Non Uniform
Speed:- distance travelled by a body per unit time ……….
speed = distance/time
Speed is scalar
Speedometer and Odometer are used to measure speed of an object
Speed
Average speed :- The average speed of a body is the total distance travelled by the total time taken.
Average Speed = Total distance traveled / Total time taken
Uniform speed :- When the rate of change of position per unit time remains same the it is called uniform speed.
Average and Uniform Speed
Velocity :- distance travelled by a body per unit time in a given direction……
VELOCITY = displacement / time
Velocity is vector.
Direction of a body is as displacement at the body.
Velocity
Uniform velocity :- When the rate of change of position per unit time remains same the it is called uniform velocity.
Velocity of a body can be changed in the following 2 ways.By changing the speed of the bodyBy keeping the speed constant but by changing the direction
Uniform Velocity
Average velocity :-
V = u + v t
Average Velocity
Acceleration
•The rate of change of velocity of an moving object is known as its Acceleration.
• It is a vector quantity.
•Acceleration = Velocity/Time
• It’s unit is m/sec2.
Retardation
• The rate of decreasing of velocity of a moving object is known as retardation.
• It is also a vector quantity.
- Prateek Saxena 9th B14