A typical walking speed is two meters per second. Probably the fastest speed for running (by people) is about ten meters per second -- 100 meters in 10 seconds.
An American Football field is 91.44 meters long, from goal line to goal line. At two meters per second, you can walk that far in 45 or 46 seconds.
Timing yourself with a watch with a second hand, how long does it take you to walk 91.44 meters?
(Mathematical experiment.)
The distance between bases on a baseball field is 27.432 meters. You can time a batter from home plate to first base to estimate the batter's speed. Somebody stealing second base might not start from first base, but if a player "tags up" you can time between other bases.
Thursday, August 14, 2008
Walking in kilometers
Today, we walked 4 kilometers (4000 meters) in 33 minutes and 27 seconds. What was our speed in meters per second? Hint: convert minutes to seconds, add 27 to get seconds. Divide to get meters per second.
Answer: very close to 2 meters per second.
Is this reasonable: make chalk marks, 2 meters apart. Start walking at one-Mississippi, hit the first chalk mark at two-Mississippi, can you hit the second chalk mark at three-Mississippi?
Answer: very close to 2 meters per second.
Is this reasonable: make chalk marks, 2 meters apart. Start walking at one-Mississippi, hit the first chalk mark at two-Mississippi, can you hit the second chalk mark at three-Mississippi?
Wednesday, August 13, 2008
Walking in kilometers
Yesterday, it was raining. Umbrellas slowed our walk. It took us 36 minutes to walk 4 kilometers, but these numbers should make computation easy. What was our speed in kilometers per hour?
Hint: convert 36 minutes to fraction of an hour, then divide 4 kilometers by this fraction to get kilometers per hour. Dividing by a fraction divides the mathematicians from the non-mathematicians, so if you have any trouble, let me know.
Answer: Between VI and VII kilometers per hour.
In new Minnesota Science standards, all computations are in meters, kilograms and seconds. What was our speed in meters per second? Hint: convert 4 kilometers to 4000 meters and 36 minutes to seconds, then divide. You will get an answer that is roughly 2 meters per second.
This is advanced, but the exact answer is 50/27 meters per second. 50/27 has a repeating decimal expansion, 1.851 851 851 you can write as 1.851 with a bar over the "851"
You could lay out 2 meters on the ground and see if you can walk that far in a second. Elementary-school students may need to jog. Start on two-Mississippi and see if you finish by three-Mississippi.
Wind speeds in Canada are given in meters per second and in the United States, in knots (nautical miles per hour). It is handy that the conversion from one to the other is close to "two;" double meters per second to get knots (approximately).
Hint: convert 36 minutes to fraction of an hour, then divide 4 kilometers by this fraction to get kilometers per hour. Dividing by a fraction divides the mathematicians from the non-mathematicians, so if you have any trouble, let me know.
Answer: Between VI and VII kilometers per hour.
In new Minnesota Science standards, all computations are in meters, kilograms and seconds. What was our speed in meters per second? Hint: convert 4 kilometers to 4000 meters and 36 minutes to seconds, then divide. You will get an answer that is roughly 2 meters per second.
This is advanced, but the exact answer is 50/27 meters per second. 50/27 has a repeating decimal expansion, 1.851 851 851 you can write as 1.851 with a bar over the "851"
You could lay out 2 meters on the ground and see if you can walk that far in a second. Elementary-school students may need to jog. Start on two-Mississippi and see if you finish by three-Mississippi.
Wind speeds in Canada are given in meters per second and in the United States, in knots (nautical miles per hour). It is handy that the conversion from one to the other is close to "two;" double meters per second to get knots (approximately).
Subscribe to:
Posts (Atom)
