Answer :
Answer:3.96 m/s
Explanation:
Given
Rock is thrown to a height of 0.8 m
We know that energy is conserved
Total Energy=kinetic Energy+Potential Energy
At bottom Kinetic Energy is maximum and Potential energy is minimum while at the top potential Energy is maximum and kinetic energy is minimum
Energy at Bottom [tex]E_b=\frac{1}{2}mv^2+0[/tex]
Energy at Top [tex]E_t=0+mgh[/tex]
Thus
[tex]E_t=E_b[/tex]
[tex]mgh=\frac{1}{2}mv^2[/tex]
[tex]v=\sqrt{2gh}[/tex]
[tex]v=\sqrt{2\times 9.8\times 0.8}[/tex]
[tex]v=\sqrt{15.68}[/tex]
[tex]v=3.96\ m/s[/tex]