Question:
An athlete takes 15 hours to finish a race of 75 km. Calculate the speed of athlete in meter per second.
Correct Answer
1.389 m/s
Solution And Explanation
[Strategy to solve the Question: First of all, calculate the speed in km/h and then change this speed in meter per second. (2) change the distance into meter and time into second and then calculate the speed using these units, i.e. meter and second. This speed will be in the required meter per second]
Calculation of speed in km/h using formula
Given, Distance = 75 km
Time = 15 hour
We know that,
Speed = Distance covered/Time
Therefore, speed = 75 5 km/15 hour
⇒ Speed = 5 km/h
Conversion of km/h into meter/second
We know that to convert km/h, we need to multiply the given speed in km/h by 5/18
Thus, 5 km/h
= 5 × 5/18
= 25/18
= 1.389 m/second
Thus, speed = 1.389 m/s Answer.
Calculation of speed in m/s using formula after changing the km to meter and time to hour
Given,
Distance = 75 km
= 75 × 1000 meter
[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]
⇒ Distance = 75000 meter
Time = 15 hour
= 15 × 60 × 60 second
[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]
⇒ Time = 54000 second
Now, we know that
Speed = Distance/Time
⇒ Speed = 75000 meter/54000 second
= 75 /54 m/s
= 1.389 m/s
Thus, speed = 1.389 m/s Answer
Unitary Method to calculate the speed using distance and time
Given, Distance = 75 km
= 75 × 1000 meter
[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]
⇒ Distance = 75000 meter
Time = 5 hour
= 5 × 60 × 60 second
[∵ 1 hour = 60 × 60 second = 3600 second]
⇒ Time = 54000 second
∵ In 54000 second, the distance covered by the athlete = 75000 meter
∴ In 1 second, the distance covered by the athlete
= 75000 meter/54000 second
= 75 meter/54 second
= 1.389 meter per second
⇒ Speed = 1.389 m/s Answer
Similar Questions
(1) After spotting a deer at a distance of 500 m, a tiger takes 1 minute 05 second to catch the prey. If after spotting the deer, the tiger takes about 15 second in thinking and then starts running, then find the speed of the tiger in kilometre per hour.
(2) At a certain speed a scooty covers a distance of 2 km in 4 hours. How much distance will it cover in 5 hour?
(3) By running at a speed of 43 km/h how much distance a motor bike will cover in 8 second?
(4) By running at a speed of 6 km/h how much distance a car will cover in 5 second?
(5) By running at a speed of 29 km/h how much distance a motor bike will cover in 8 second?
(6) Find the distance covered by a bus in 24 hours if it covers a distance of 60 km in 14 hours.
(7) Find the distance covered by a bus in 24 hours if it covers a distance of 86 km in 14 hours.
(8) By running at a speed of 16 km/h how much distance a motor bike will cover in 8 second?
(9) By running at a speed of 23 km/h how much distance a scooty will cover in 7 second?
(10) By running at a speed of 19 km/h how much distance a motor bike will cover in 8 second?