A girl who weighs 56 kg is skiing at a mountain. She is moving @ 16m/s across the crest of a ski hill located 34 m above the ground level at the end of the run.
a) Determine her potential energy relative to the height of the ground at the end of the run.
answer = 10 000 J
I don't know how to get that answer and I need your help!!!
What I tried to do:
Eg = mgh
= (56 kg)(9.8 N/kg)(34 m)
= 18659.2 J
I don't know what I'm doing wrong xD
Please show step by step.
Thank you in advance (will award best answer)
a) Determine her potential energy relative to the height of the ground at the end of the run.
answer = 10 000 J
I don't know how to get that answer and I need your help!!!
What I tried to do:
Eg = mgh
= (56 kg)(9.8 N/kg)(34 m)
= 18659.2 J
I don't know what I'm doing wrong xD
Please show step by step.
Thank you in advance (will award best answer)
-
U have the diagram and we don't :>)
The skier U describe has:
KE = 1/2mV² = (0.5)(56)(16)² = 7168 J
at the crest of a hill that is supposedly 34 m above ground level.
but
U correctly compute the GPE (gravitational potential energy) = mgh = 18659 J
when skier is 34 m above ground...so the GPE of 10,000 J would be at a lower height.
If I suppose that the GPE = 10,000 J then the skier's height above ground would be:
mgh = 10,000
(56)(9.8)h = 10,000
h = 10,000/(56)(9.8) = 18.2 m <=
and with the KE of the skier added the total skier's ME = 17,168 J
which would come from a ski start hill of height = h:
where mgh = 17,168 J
h = 17,168/(9.8)(56) = 31.3 m <= max height of starting hill
The skier U describe has:
KE = 1/2mV² = (0.5)(56)(16)² = 7168 J
at the crest of a hill that is supposedly 34 m above ground level.
but
U correctly compute the GPE (gravitational potential energy) = mgh = 18659 J
when skier is 34 m above ground...so the GPE of 10,000 J would be at a lower height.
If I suppose that the GPE = 10,000 J then the skier's height above ground would be:
mgh = 10,000
(56)(9.8)h = 10,000
h = 10,000/(56)(9.8) = 18.2 m <=
and with the KE of the skier added the total skier's ME = 17,168 J
which would come from a ski start hill of height = h:
where mgh = 17,168 J
h = 17,168/(9.8)(56) = 31.3 m <= max height of starting hill
-
Your answer is exactly right. Don't let anyone tell you it's wrong.