Answer
a) At h = 20m,
KE = 0 J
GPE = 392 J
Total E = 392 J
b) At h = 10m,
KE = 196 J
GPE = 196 J
Total E = 392 J
c) At h = 0m,
KE = 392 J
GPE = 0 J
Total E = 392 J
Work Step by Step
a) At h = 20m
GPE = mg$\Delta$h
= 2(9.8)(20)
= 392 J
KE = 0 J
Total E = 392 J
b) At h = 10m,
GPE = mg$\Delta$h
= 2(9.8)(10)
= 196 J
Total E = 392 J
KE = Total E - GPE
= 392 - 196
= 196 J
c) At h = 0m,
GPE = 0 J
Total E = 392 J
KE = 392 J
