When you drop an object like a stone it picks up speed as it falls, as its PE is converted to KE. But what happens when you drop a feather? If you dropped a feather in a vaccuum it would pick up speed just like a rock does, and its PE would be convereted to KE as it falls. But with air resistance what happens? The feather floats gently to the ground, gathering only a small amount of velocity (and small amount of KE) when you initially let go, but then its velocity remains constant for the remainder of the fall. So where does the PE go, if not into KE? Hint: does air resistance come into play here? If so - what happens to energy lost to mechanical resistannce?
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