Gita takes 2 hours to reach the airport from her home by car. Calculate the distance between her home and the airport if the car has a speed of 40 km/hr. Convert the speed to standard units.
Answers
Answer:Here we will learn the conversion of units of speed
(i) Conversion of km/hr into m/sec
(ii) Conversion of m/sec to km/hr
How to convert km/hr into m/sec?
km/hr = 1 km/1 hr = 1 × 1000 m/60 × 60 sec = 1000/3600 m/sec = 5/18 m/sec
So, we say that to convert km/hr into m/sec, we multiply by 5/18.
Solved examples on conversion of km/hr into m/sec:
1. Convert 72 km/hr to m/sec
Solution:
72 km/hr
= 72 × 5/18 m/sec
= 20 m/sec
2. The speed of the bicycle is 90 km/hr, what is its speed in m/sec?
Solution:
Speed of bicycle = 90 km/hr
To convert the speed into m/sec, we multiply by 5/18
Therefore, speed of bicycle = 90 × 5/18 m/sec = 25 m/sec
3. A car covers a distance of 100 km in first two hours, 120 km in next 1 hour and 32 km in next 1/2 hour. Convert the speed into m/sec.
Solution:
Total distance covered by the car = (100 + 120 + 32) km = 252km
Total time taken = (2 + 1 + 1/2) hr = (4 + 2 + 1)/2 = 7/2 hr
Therefore, average speed = Distance covered/Time taken
= 252 km/(7/2) hr
= 252/1 × 2/7 km/hr
= 72 km/hr
To convert the speed into m/sec, we multiply by 5/18
Therefore, 72 km/hr = 72 × 5/18 = 20 m/sec
How to convert m/sec to km/hr?
m/sec = 1m/1sec = (1/1000) km/(1/60 × 60) hr = 60 × 60 /1000 km/hr = 18/5 km/hr
So, we say that to convert m/sec into km/hr, we multiply by 18/5
Solved examples on conversion of km/hr into m/sec:
1. Convert 40 m/sec to km/hr
Solution:
40m/sec
= 40 × 18/5
= 144 km/hr
2. The speed of a cyclist is 4 m/sec. find the speed in km/hr.
Solution:
Speed of a cyclist = 4 m/sec
To convert the speed in km/hr, we multiply by 18/5
Therefore, speed of the cyclist = 4 × 18/5 km/hr
= 72/5 km/hr
= 14.4 km/hr
Hence, we have learnt the conversion of units of speed from km/hr to m/sec and m/sec to km/hr.
Explanation: