[tex]\displaystyle Se~da:\\ \\
k=3s\\ \\
d=5cm=0,05m\\ \\
\tau=12s\\ \\
v=?\frac ms\\ \\ \\
Formule:\\ \\
In~a~k~secunda~corpul~parcurge:\\ \\
d=v_0\times 1+\frac{a\times 1^2}{2}=v_0+\frac a2\\ \\ \\
v_0~este~viteza~la~sfirsitul~secundei~2(k-1)\\ \\
v_0=a\times (k-1)\\ \\ \\[/tex]
[tex]\displaystyle Inlocuind:\\ \\
d=a\times(k-1)+\frac a2\\ \\
d=a\times(k-1+0,5)=a\times(k-0,5)\\ \\
a=\frac{d}{k-0,5}\\ \\ \\
v=a\times \tau=\frac{d\times \tau}{k-0,5}\\ \\ \\
Calcule:\\ \\
v=\frac{0,05\times 12}{3-0,5}=0,24\frac ms[/tex]