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/s, reaching an ultimate height of 20 cm.
A)

What fraction of the initial kinetic energy is converted to the final potential energy?

Express your answer numerically.

UfKi =

B)

What happens to the "lost" energy?

Choose the correct answer

It has been transformed into thermal energy of the spores and surrounding air.
It has been transformed into thermal energy of the spores and potential energy of surrounding air.
It has been transformed into potential energy of the spores and kinetic energy of surrounding air.
It has been transformed into potential energy of the spores and surrounding air.

Answer 1

Answer:

$Em_{f}$ / Em₀ = 0.30

Explanation:

In this exercise we use the relationship of mechanical energy, kinetic energy and gravitational potential energy

      K = ½ m v²

      U = mgh

We calculate the mechanical energy at two points

Initial. Lower

    Em₀ = K = ½ m v²

Highest finish

    $Em_{f}$= U = mg and

Let's calculate

    Em₀ = ½ m 3.6 2

    Em₀ = m 6.48

    $Em_{f}$ = m 9.8 0.20

    $Em_{f}$= m 1.96

The fraction of lost energy is

    $Em_{f}$ / Em₀ = m 1.96 / m 6.48

   $Em_{f}$ / Em₀ = 0.30

30% sun is converted into potential energy

It has several transformation possibilities

It is transformed into thermal energy of air and spores, since this energy cannot be recovered