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Homework Help: Help! challenging problem on energy and projectile motion

  1. Jun 25, 2009 #1
    One winter break, while visiting Scotland's Loch Ness, you stop to tour the ruins of Urquhart
    Castle, which are found on the loch's western shore. A truck carrying barrels passes and, as it does, a
    sealed barrel and a spare lid fall from the truck and land by the side of the road. The barrel comes to
    rest at the very top of the snowy slope that leads down to the loch's shoreline. A few moments later, the
    wind from the next car is just enough to push the barrel over the edge to slide, not roll, down the slick
    slope. Once the barrel reaches the bottom, it begins to roll across the level shore. It rolls over exactly 3
    times before rolling into a tree branch at the water's edge. Upon hitting the branch, the barrel is
    knocked up and into the air, at what appears to be a 45 degree angle. It flies through the air for about 2
    seconds before landing in the water. After it is in the water for a few moments, you notice that the
    barrel is floating right side up with about half of it above the surface. To your astonishment, a small
    aquatic creature, the likes of which you have never seen, begins to play with the barrel. Following one
    particularly strong nudge to the barrel, which leaves the barrel bobbing up and down in the water, the
    creature is scared away by shouts from other tourists. After recording that the barrel bobs up and down
    once every 2.4 seconds you walk along the road to further investigate what you have just witnessed.
    Your investigation reveals that the mass of the spare lid is 6.8 kg, the road is 14m above the shore, and
    that distance from the bottom of the slope to the water's edge is 5.4m.
    Now, you have enough information to answer a very important question, namely, was there any
    whiskey in the barrel and, if so, how much?
  2. jcsd
  3. Jun 25, 2009 #2


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