Question

(b) repeat this problem with the zero - level at point \textcircled{a}.
pe_i = 0 j
pe_f=-6114.6 j
delta pe=-6114.6 j
(c) repeat again, with the zero level 2.00 m higher than point \textcircled{b}.
pe_i = 5012.76 j
pe_f=-1117.2 j
delta pe=-6129.96 j
exercise
hints: getting started | im stuck!
use the values from practice it to help you work this exercise. if the zero level for the gravitational potential energy is selected to be midway down the slope, 5.50 m above point \textcircled{b}, find the initial potential energy, the final potential energy, and the change in potential energy as the skier goes from point \textcircled{a} to \textcircled{b} in the figure.
initial 3057.3 your response is off by a multiple of ten. kj
final - 3057.3 your response is off by a multiple of ten. kj
change - 6114.6 your response is off by a multiple of ten. kj

Explanation:

Step1: Recall gravitational - potential - energy formula

$PE = mgh$, where $m$ is mass, $g$ is acceleration due to gravity ($g=9.8\ m/s^{2}$), and $h$ is height relative to zero - level.

Step2: Determine height differences

Let's assume we know the mass of the skier and the height of point A and B relative to the new zero - level (midway down the slope, 5.50 m above point B). Calculate the initial height $h_i$ of point A relative to the new zero - level and the final height $h_f$ of point B relative to the new zero - level.

Step3: Calculate initial potential energy

$PE_i=mgh_i$.

Step4: Calculate final potential energy

$PE_f = mgh_f$.

Step5: Calculate change in potential energy

$\Delta PE=PE_f - PE_i$.

Answer:

We need the mass of the skier and the height of point A relative to point B to calculate the exact values. But the general steps are as above. If we assume the mass of the skier is $m$ and the height of point A above point B is $H$. The height of point A above the new zero - level is $h_A$ and height of point B above new zero - level is $h_B = 0$. Then $PE_i = mgh_A$, $PE_f=0$, and $\Delta PE=-mgh_A$.