Dear John,
To put your thoughts into context, you might like to consider some of
the (rounded) values in this table:
Activity
Speed
(km/h)
Speed
(m/min)
Speed
(m/s)
Walking – slowly
4 km/h
60 m/min
1 m/s
Walking – briskly
6 km/h
100 m/min
1.7 m/s
Walking – march time
5 km/h
90 m/min
1.5 m/s
Jogging
15 km/h
240 m/min
4 m/s
Running
20 km/h
360 m/min
6 m/s
Sprinting (~world record)
36 km/h
600 m/min
10 m/s
Running rabbit
55 km/h
900 m/min
15 m/s
Falcon or raptor diving
70 km/h
1200 m/min
20 m/s
Highway
100 km/h
1667 m/min
27 m/s
Interstate highway
110 km/h
1833 m/min
31 m/s
Suburban street
60 km/h
1000 m/min
17 m/s
I particularly like the 'Brisk walk' figure of 100 metres per minute
that could be useful on walking paths to give people a goal as they
walk for fitness. To do this you need to place markers every 100
metres along a popular walking path. I have explored this further in
the article: Walking for fitness that you can find at http://www.metricationmatters.com/docs/WalkingForFitness.pdf
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that they
now save thousands each year when buying, processing, or selling for
their businesses. Pat provides services and resources for many
different trades, crafts, and professions for commercial, industrial
and government metrication leaders in Asia, Europe, and in the USA.
Pat's clients include the Australian Government, Google, NASA, NIST,
and the metric associations of Canada, the UK, and the USA. See http://www.metricationmatters.com
for more metrication information, contact Pat at pat.naugh...@metricationmatters.com
or to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
On 2009/07/15, at 5:02 PM, John Frewen-Lord wrote:
I am not convinced! One of the criteria needed in driving on the
roads is the need to provide some form of relationship between speed
and distance over time we that can relate to. If distance is
measured in km, then speed needs to also use km, and km/h is as
convenient a measure as any.
I once wrote to Road and Track (US auto magazine) providing a
counter argument to technical editor Denis Simonaitis's (I think
that is how his name is spelled) assertion that imperial measures
have some handy 'yardsticks', such as 60 mph is equal to 1 mile per
minute. My argument was that metric has even more (and better):
1. Urban journeys are generally measured in minutes. A good urban
average is 60 km/h (equal to 1 km per minute), therefore a journey
of say 15 km will take 15 minutes.
2. Long distance journeys are generally measured in hours. A good
freeway average is 100 km/h, therefore a journey of 450 km will take
4.5 hours.
3. And a (perhaps slightly over the speed limit) rate of progress
on the freeway of 120 km/h will mean that the kilometres are
slipping by at the rate of 2 km per minute - useful in calculating
the time to your next exit.
I was quite gratified that Denis devoted a good section of his next
article in putting my case forward.
I cannot see though how the use of m/s would fit in with any of the
above, as metres (except in short distances to intersections and the
like) are not used in measuring travel distances on the roads, and
seconds are not used to measure time taken.
Regards
John F-L
----- Original Message -----
From: Pat Naughtin
To: U.S. Metric Association
Sent: Wednesday, July 15, 2009 1:47 AM
Subject: [USMA:45365] Speed in metres per second
Dear All,
I have just been reading this blog at http://globonsomeday.blogspot.com/2009/07/improving-metric-system.html
where they say:
Another metric unit commonly encountered in everyday usage is the
unit of speed, kilometres per hour. The official SI base unit for
time is seconds, and therefore a more appropriate measurement of
speed is metres per second. For example, 100 km/h is equivalent to
27.78 m/s.
I wonder if we will ever be ready to embrace the idea of using the
SI unit, metres per second, for speed in everyday conversations.
Let's take the example given above with sensible rounding. The speed
limit on a highway might then become 25 metres per second.
Other limits might go like this (using Australian examples):
School zone 40 km/h 10 m/s
Suburban street 60 km/h 15 m/s
Main (4 lane) cross town road 70 km/h 20 m/s
Highway 100 km/h 25 m/s
Freeway 110 km/h 30 m/s
It might be interesting to see this idea applied to speed limits in
Asia, Europe, the UK and the USA.
Cheers,
Pat Naughtin
Author of the forthcoming book, Metrication Leaders Guide.
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
helped thousands of people and hundreds of companies upgrade to the
modern metric system smoothly, quickly, and so economically that
they now save thousands each year when buying, processing, or
selling for their businesses. Pat provides services and resources
for many different trades, crafts, and professions for commercial,
industrial and government metrication leaders in Asia, Europe, and
in the USA. Pat's clients include the Australian Government, Google,
NASA, NIST, and the metric associations of Canada, the UK, and the
USA. See http://www.metricationmatters.com for more metrication
information, contact Pat at pat.naugh...@metricationmatters.com or
to get the free 'Metrication matters' newsletter go to: http://www.metricationmatters.com/newsletter
to subscribe.
