本题目来源于试卷: newnewnewnew,类别为 IB物理学
[问答题]
A block is given a push so that it slides up afw9tlk5 ) m/ioduu o)--d njr)thii28 ramp. After the /jv 6gpwwzq(b9-4si n block reaches its highest point, it s/( js94i-wbpqz gn6 wvlides back down but the magnitude of its acceleration is less on the descent than on the ascent. Why?
参考答案: On the way up, there are two forces on the block that are parallel to each other causing the deceleration – the component of weight parallel to the plane, and the force of friction on the block. Since the forces are parallel to each other, both pointing down the plane, they add, causing a larger magnitude force and a larger acceleration. On the way down, those same two forces are opposite of each other, because the force of friction is now directed up the plane. With these two forces being opposite of each other, their net force is smaller, and so the acceleration is smaller.
本题详细解析:
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