I am working on Measurements and it is one of the most difficult things for me to do. Topics include the SI measurement, Imperial Measurement, and Converting between SI and Imperial Systems.
I would like to do some review on this and would like to know a easier way to all problems.
Montgomery ran 100m in 9.78s. What was the runner's speed in kilometres per hour?
How do I do this? Do I convert metres to kilometres first? How do I convert seconds to hours? I just don't get it . Can someone please provide me with clarification.
maybe this will make sense to you .....
100 m = .1 km
and 1 sec = 1/(60x60) or 1/3600 hour
so 100 m/9.78 sec
= .1 km/(9.78 x 1/3600) hr
= 36.8 km/hr
or look at it this way ...
there are 3600 seconds in 1 hour.
so by dividing 3600 by 9.78 we would get 368 legs of 100 m, but 10 of those 100 stretches make 1 km, so divide 368 by 10 to find the number of km
or 36.8 km/hr
I would simply form a ratio using the same units the same units
.1 km/9.78 sec = xkm/3600 sec
cross multiply
9.78x = .1(3600)
x = 360/9.78
x = 36.8
so x = 36.8 km/3600 sec
= 36.8 km/hr
That does make a lot of sense, thank you very much Reiny!
To find the runner's speed in kilometers per hour, you will need to convert both the distance and time measurements.
First, let's convert the distance from meters to kilometers. Since there are 1,000 meters in a kilometer, you can divide the distance of 100 meters by 1,000 to get 0.1 kilometers.
Next, let's convert the time from seconds to hours. Since there are 60 seconds in a minute and 60 minutes in an hour, you can divide the time of 9.78 seconds by 60 to get the number of minutes and then divide the result by 60 again to get the number of hours.
To calculate that, you can divide 9.78 by 60 to get approximately 0.163 minutes, and then divide 0.163 by 60 to get approximately 0.003 hours.
Now that you have the distance of 0.1 kilometers and the time of 0.003 hours, you can calculate the speed by dividing the distance by the time.
So, the runner's speed in kilometers per hour is:
Speed = Distance / Time
Speed = 0.1 km / 0.003 hours
Speed ≈ 33.33 km/h
Therefore, Montgomery's speed is approximately 33.33 kilometers per hour.