Question

Mosses don't spread by dispersing seeds; they disperse tiny spores. The spores are so small that they will stay aloft and move with the wind, but getting them to be windborne requires the moss to shoot the spores upward. Some species do this by using a spore-containing capsule that dries out and shrinks. The pressure of the air trapped inside the capsule increases. At a certain point, the capsule pops, and a stream of spores is ejected upward at 3.6 m/sm/s, reaching an ultimate height of 20 cm.
Required:
What fraction of the initial kinetic energy is converted to the final potential energy?

Answer 1

Answer:

  U / K = 0.30

Explanation:

For this exercise we must calculate the energy at the two points.

Initial. Where are the spores

       K = ½ m v²2

Final. Higher

        U = m g h

the fraction of energy is

          U / K = 2gh /v²

let's calculate

           U / K = 2  9.8  0.20 / 3.6²

            U / K = 0.30

therefore 30% of the energy is lost