[題目] 鉛直SHM
[領域]簡諧運動
[來源]吳笛物理
[題目]1kg物體由距鉛直彈簧1m處鉛直落下 k=100N/m
問最大壓縮量和最大速度
[瓶頸]
最大壓縮量: mg(1+x)=0.5kx^2
x=0.56m
沒問題
但是看解答
平衡時v(max)
此時0.5mv^2=mgh-0.5kx^2=1*10*1.1-0.5*100*0.1^2
v=4.6m/s
看不懂
我用的是力學能守恒
0.5kx^2+0.5mv^2=定值
x=由平衡點算起的位移
最大位能=0.5k^(0.56-0.1)^2=最大動能=0.5*1*v^2
v=4.6 m/s
這是碰巧算對嗎
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