Data:
When you have two variables directly proportional they follows the next:
If the variables are time (t) and speed (s):
[tex]\frac{s_1}{t_1}=\frac{s_2}{t_2}[/tex]
Then, if you have:
t1=3
s1=16.5
t2=7
s2=?
[tex]\begin{gathered} \frac{16.5}{3}=\frac{s_2}{7} \\ \\ \frac{7(16.5)}{3}=s_2 \\ \\ s_2=\frac{115.5}{3}=38.5 \end{gathered}[/tex]
Then, if the object has fallen for 7 second its speed is 38.5m/s
