Question

Need help with these. Short straight forward answers please :)

Answer 1

We will have the following:

3.

a. The gravitational potential energy will be:

`E_g=(60kg)(9.8m/s^2)(10m)\Rightarrow E_g=5880J`

So, the gravitational potential energy at the beginning will be 5880 J.

b. The total kinetic energy just before hitting the ground will be 5880 J.

The velocity will be 14 m/s.

4.

a. First, we determine the gravitational potential energy and the kinetic energy at the bottom:

`\begin{gathered} E_g=(60kg)(9.8m/s^2)(15m)\Rightarrow E_g=8820J \\ \\ and \\ \\ K=(1)/(2)(60kg)(4m/s)^2\Rightarrow K=480J \end{gathered}`

So, of Rhoda hit a dry spot a total of 8340 J of energy was dissipated due to friction.

b. The percentage of energy dissipated was approximately 94.56%.