Answer:
Speed, s = 3.95 m/s
Explanation:
It is given that, a rock is thrown 0.8 meters into the air. We have to find the velocity with which it is thrown.
Using conservation of mechanical energy as :
\(K_i+P_i=K_f+P_f\)
Initial potential energy at the ground is 0 and at maximum height the final kinetic energy is 0.
So,
\(\dfrac{1}{2}mv^2=mgh\)
\(v=\sqrt{2gh}\)
putting g = 9.8 m/s² and h = 0.8 m
\(v=\sqrt{2\times 9.8\times 0.8}\)
v = 3.95 m/s
Hence, it was thrown with a speed of 3.95 m/s
