An object in free fall from a height of 80 m on the ground with coefficient of restitution is 0,2, the speed of the reflected object is ... .

[tex]e = \sqrt{ \frac{h'}{h}} [/tex]
[tex]0.2 = \sqrt{ \frac{h'}{80}} [/tex]
[tex](0.2)^2 = \sqrt{ \frac{h'}{80}}[/tex]
[tex]4. 10^{-2} = \frac{h'}{80} [/tex]
∴[tex]h'=3,2[/tex]
[tex]v= \sqrt{2.g.h'} [/tex]
[tex]v= \sqrt{2.3,2.10} [/tex]
[tex]v = \sqrt{64} [/tex]
[tex]v=8[/tex]