1) Calculate the speed of a runner who runs 100 m in 20s

This is how you calculate his speed, for the 100metres. That is, the average speed for the entire distance, including the start from intertia until the race end where the athlete is decelerating. Multiply the time by 10, and divide 3600 by that figure. i.e. 10 by10 equals 100. Divide 3600 by 100 and you get 36 which is the speed figure you requested.

A female athlete ran 200 metres a few years ago and in the middle section of the race covered 100 metres in that race in a time under 10 seconds. That is, she ran a sub 10second 100metres from a flying start. This great athlete from Slovenia, also ran a 100 metre race (from a stationary start) in a time under 11 seconds, when she was 48 years of age. Her name is Merlene Ottey.

show the wavelengths of a wave. show the crests of a wave.

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