Question

Suppose a 345-g kookaburra (a large kingfisher bird) picks up a 75-g snake and raises it 2.1 m from the ground to a branch.How much work, in joules, did the bird do on the snake? How much work, in joules, did it do to raise its own center of mass to the branch?

Answer 1

The work done in each case can be calculated with the change in potential energy of the body:

`Work=m\cdot g\cdot h`

The work done by the bird on the snake will use only the mass of the snake (in kg):

`\begin{gathered} Work=0.075\cdot9.8\cdot2.1\\ \\ Work=1.5435\text{ J} \end{gathered}`

The work done by the bird to raise its own center of mass will use only the bird mass (in kg):

`\begin{gathered} Work=0.345\cdot9.8\cdot2.1\\ \\ Work=7.1\text{ J} \end{gathered}`