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golderhadashaowtatz
21.08.2019 •
Physics
What is the average speed of a cyclist on a 14 mike bike trail that takes 1 hour and 10 minutes
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Ответ:
Let's find how long it takes to fall 75 meters:
s(t) = Vi + (1/2)*a*t²,
where s(t) is displacement as a function of time, Vi is initial velocity (zero), and a is acceleration. Plugging in our values:
-75 = 0 + (1/2)(-9.8)(t²) Multiply both sides by 2/-9.8
15.3 = t² Take the square root of both sides
t = 3.91
We need to the ball to travel 20 meters horizontally before it hits the roof in 3.91 seconds. We can assume that the horizontal velocity remains constant (a=0, Vi=V(t) for all t).
Therefore, the minimum horizontal velocity is:
D = V*t , simple distance formula, distance equals velocity times time:
20 = V * 3.91 Divide both sides by 3.91
V = 5.11
The horizontal velocity, therefore, must be at least 5.11m/s in order for the ball to reach the roof of the second building.