The question here is how long does it take for a falling
person to reach the 90% of this terminal velocity. The computation is:
The terminal velocity vt fulfills v'=0. Therefore vt=g/c,
and so c=g/vt = 10/(100*1000/3600) = 36,000/100,000... /s. Incorporating the
differential equation shows that the time needed to reach velocity v is
t= ln [g / (g-c*v)] / c.
With v=.9 vt =.9 g/c,
t = ln [10] /c = 6.4 sec.
Answer:

Step-by-step explanation:

First, let's start off with the information we already have. Since the ratio is 4 boys to 5 girls, there has to be a minimum of 9 students (4 being boys and 5 being girls).
9 will be the denominator of both of our fractions since the boys and girls are in the same class.
The fraction of boys in the class is 4/9 (since there are 4 boys to 5 girls in a class of 9, we would write 4 over 9) and the fraction of girls in the class is 5/9.
This is a simplified version of the fractions. If this is a multiple-answer question and 4/9 and 5/9 are not up there, try multiplying the fractions with different numbers and see what fractions will be correct.
But either way, 4/9 and 5/9 are correct :)
Answer: 120
Step-by-step explanation:
Given : The league championship 800 meter race has 6 runners.
The number of positions = 3
Since order matters here , so we use Permutation.
The permutation of n things taking r at a time is given by :-

Then, the number of different ways they place first, second, and third :_

Hence, they can place first, second, and third in 120 different ways .