- #1
BlackMamba
- 187
- 0
Hello,
I could use a little guidance on this problem.
An extreme skier, starting from rest, coasts down a mountain that makes an angle of 25 degrees with the horizontal. The coefficient of kinetic friction between her skis and the snow is 0.200. She coasts for a distance of 13.1m before comming to the edge of a cliff. Without slowing down, she skis off the cliff and lands downhill at a point whose vertical distance is 3.30m below the edge. How fast is she going just before she lands?
So here is my reasoning and what I have done thus far. I drew my free body diagram which really doesn't really do anything for me, but I know it is supposed to. Anyway, I also drew a little picture of what the hill and skier might look like.
I decided that to find the initial height I would use 13.1m(sin 25) to get the inital height. I know that the final height is 3.30m. I also know that initial velocity is 0 since she is starting from rest and I'm left to find the final velocity. So here's my little chart.
Ho = 5.54
Hf = 3.30
Vo = 0
Vf = ?
So forgetting about the friction for a moment I found the velocity the skier would be traveling at the landing point using this equation: Vf = square root of Vo^2 + 2g(Ho - Hf)
But I know that isn't the answer because I didn't take the friction into consideration. Thus my question. How do I fit that in there? This is the part that is stumping me. Perhaps I should have used a different equation to include the friction but I don't have the slightest clue what that could be.
Any help provided would be greatly appreciated.
I could use a little guidance on this problem.
An extreme skier, starting from rest, coasts down a mountain that makes an angle of 25 degrees with the horizontal. The coefficient of kinetic friction between her skis and the snow is 0.200. She coasts for a distance of 13.1m before comming to the edge of a cliff. Without slowing down, she skis off the cliff and lands downhill at a point whose vertical distance is 3.30m below the edge. How fast is she going just before she lands?
So here is my reasoning and what I have done thus far. I drew my free body diagram which really doesn't really do anything for me, but I know it is supposed to. Anyway, I also drew a little picture of what the hill and skier might look like.
I decided that to find the initial height I would use 13.1m(sin 25) to get the inital height. I know that the final height is 3.30m. I also know that initial velocity is 0 since she is starting from rest and I'm left to find the final velocity. So here's my little chart.
Ho = 5.54
Hf = 3.30
Vo = 0
Vf = ?
So forgetting about the friction for a moment I found the velocity the skier would be traveling at the landing point using this equation: Vf = square root of Vo^2 + 2g(Ho - Hf)
But I know that isn't the answer because I didn't take the friction into consideration. Thus my question. How do I fit that in there? This is the part that is stumping me. Perhaps I should have used a different equation to include the friction but I don't have the slightest clue what that could be.
Any help provided would be greatly appreciated.