SPEED AND DISTANCE RELATED PROBLEMS:
We define speed as distance travelled in a particular time,
Speed = distance /time
but once we have the equation, we can use any of its variations,
Time = Distance/speed
Distance = speed*time
CONVERSION:
1km/hr=1000m/h=1000/3600m/sec=5/18m/sec
1 m/s = 18/5 Km/hr
1 km/hr =5/8 miles/hr
1 mile/hr = 22/15 feet/sec
average speed = total distance/total time taken