本题目来源于试卷: 美国2021年物理杯赛真题 PHYSICS BOWL 2021，类别为 美国物理杯赛(Physics Bowl)
[单选题]
A spring loaded projectile launcher launches a plastic ball horizontally with a speed of 4.0 m/s. If thespring were compressed twice as far, the ball’s launch speed would be
A. 1.0 m/s
B. 2 .0 m/s
C. 4.0 m/s
D. 8.0 m/s
E. 16 m/s
参考答案: D
本题详细解析:
P$E_E$=KE;P$E_E$=$\frac{1}{2}$kx^2 & KE=$\frac{1}{2}$mv^2
k&m don't change.so the speed is directly proporational to the compression.
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