MOTION - Vaishnavi

   MOTION

What is a motion?

   The change of the postion of an object in terms of distance moved or te displacement 

It could be uniform  or non uniform depending on whether  its velocity  is constant or changing 

Uniform motion : obeject covers equal distance onequal intervals of time

Non uniform motion:object covers unequal distances in equal intervals of time

SCALER QUANTITY : The physical quantity  in which only magnitude and direction is not specified .

ex: speed , distance

Examples 

1) The object travels 16m in 4s and then another 16m in 2s what is the average speed?

 Distance (s) =16m+16m=32m

Time taken (t) =4s+2s=6s

average  speed(v) = Distance / Time 

ie.v=s/t

=32m/6s=5.33m/s  

2) The odometer of a car reads 2000km at the start of a trip and 2400km at the end of the trip. If the trip took 8h ,calculate the average  speed of the car in km/h and m/s

  Distance covered 

s=2400km -2000km=400km

Time elapsed ,t =8h

average speed is:

 vas =s/t =400km/8h

=50km/h

=50 km/h ×1000m/1km×1h/3600

=13.9m/s

3)Usha swims in 90m long pool.she covers 180m in one min by swimming from one end to the other and back along the same straight path. Find the average speed and average  velocity of usha 

  Total distance in 1m is 180 m

Displacement of usha in 1 min = 0m

average  speed =Total distance covered /Total time taken

=180 m/1min×180m/1min ×1min/ 60s

=3m/s

average velocity=displacement /time =0m/60s=0m/s
           EXERCISE
1)An athlete completes one round of a circular track of diameter 200m in 40s. What will be the distance covered and the displacement at the end of 2min 20s?
       Diameter of the circle =200m
    Radius=100m