The formula for speed is distance÷time. The distance in this situation is 27km and the amount of time taken to cover that distance is 5 hours. Now, we substitute the values into an equation:
Speed = 27km/5h
Speed = 5.4km/h
Therefore, Desmond's speed is 5.4km/h.
There's a crest and a trough in each complete wave. So the question is describing 10 complete waves.
After that, the question becomes somewhat murky. It goes on to say "its time period is 0.2 seconds".
-- The "time period" of a wave is usually defined as the time for <u><em>one</em></u> complete wave. If that's what the phrase means, then ...
Frequency = ( 1/0.2sec )
<em>Frequency = 5 Hz.</em>
<em>= = = = = = = = = =</em>
<u>BUT</u> ... Is the question awkwardly trying to tell us that the <u><em>10 waves</em></u> take 0.2 seconds ? If that's what it's saying, then ...
Frequency = (10) / (0.2 sec)
<em>Frequency = 50 Hz .</em>
The same number there were on the reactant side, before the reaction.
