If someone runs a 100m race in 9.77 seconds, how many kilometers/hour is it?

Question

I am really confused by this, how could I convert it? Could you show me step by step please? And explain as well. I'm stuck, I figured it's about 97.7 seconds per kilometer, which is 137.7 seconds per kilometer, or 1:37.7/1

I figure then I multiply the time by 60 to get how fast it is, which I get like 90 km/hr, which is obviously completely wrong. But I checked the answers in the back of the book but it says 36.88 km/hr. HELP PLEASE!

PI R, could you explain how you got that answer please? This question has me stumped.

Mikala, I'm still a bit confused, sorry :(.

If it's 1000m per km, wouldn't I divide the 9.77 by 60 for minutes, then 60 again for hours?

UGHHH, this is so annoying.

THANKS MATHSTUDENT, that was exactly what I was looking for!!!!

Answer 1

Hi,

Since this was measured in meters/second and you want to get to kilometers per hour, you must multiply by fractions that will convert from one unit to another.

meters....kilometers
---------- x -----------
second.....meter

This cancels out the meters and leaves kilometers/second. Then since there are 60 seconds in every minute and 60 minutes in every hour, then there are 60 x 60 or 3600 second per hour. If we multiply the fractions below, we will have kilometers/hour, as desired.

kilometers.....seconds
--------------- x -----------
second.............hour

So with numbers, this is:

100.m....1.km....3600.sec
---------.x.-------.x.------------- = 36.847 km/hr
9.77sec.1000m...1.hr

I hope that helps!! :-)




36.847 km/hr

Answer 2

In these kind of problems always try to conver the parameters to required one first.
1)Convert 100m to a kilometer.
A kilometer has 1000m,so to convert 100m to a Km,divide it by 1000
100/1000=0.1Km
2)Convert 9.77 seconds to an hour.
A minute has 60 seconds and an hour has 60 minutes,so to convert this to an hour,you need to divide it by 60*60
so 9.77/(60*60)=0.0271 hour
3)Find the Speed
0.1/0.00271=36.9Km/H
You can always Verify your answer,Go to Google and enter
100m to Km and 9.77seconds to hour.

Answer 3

you are on the right track..however, you did this:

100meters/9.77 seconds into km/hour
you want to convert seconds to minutes and meters to kilometers...order does not matter.

100meters=1 km
1km/9.77 seconds


1km /9.77seconds x 60 seconds/1 min x 60mins/1 hour


ok this skewed when i typed it out...but it's:
km/sec x sec/min x min/hour..... it looks much better if you make the / straight...then cancel out and multiple

Answer 4

3600 sec = 1 hour
1000 m = 1 km

Speed = 100 / 9.77 m / sec
Speed = (100 / 9.77) x (1 / 1000) x 3600 km / h
Speed = 36 . 85 km / h

Answer 5

in 9.77 seconds he runs 100 m
Therefore in 1 second he runs 100/9.77 meter
Therefore in 1 hour or 60*60 seconds he runs (100*60*60/9.77 )meter or (100*60*60/
9.77*1000) or 36.847 km
Therefore his speed is 36.84 km/hr

Answer 6

= (100 / 1,000) / (9.77 / [60 * 60])
= (1/10) / (977 / 360,000)
= 1/10 * 360,000/977
= 36,000/977
= 36 828/977

Answer: 36.85 km/hr OR
36 kilometers, 847meters, 49 227/977 centimeters per hour

Answer 7

convert seconds to minutes and meters to kilometers...order does not matter.

100meters=1 km
1km/9.77 seconds


1km 60 seconds 60 minutes
-------- x ------------------ x ----------------------
9.77second 1 minute 1 hour


ok this skewed when i typed it out...but it's:
km/sec x sec/min x min/hour

2 minutes ago - Report Abuse

Answer 8

first you have to convert m to km (1 km = 1000 m ; 1 m = 0.001 km), and convert sec to hour (1 hour = 3600 sec; 1 sec =1/3600 hour )
second you have figure 100 m over 9.77 sec = 10.235 m/s
then 10.235 m/sec : km/hour, (convert km/hour to m/hour) so it became = 10.235 m/sec : (1000 m / 3600 sec) = so the aswer is 36.846 km/hour.