美国2021年物理杯赛真题 PHYSICS BOWL 2021 (id: 031b4af51)

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 brick is moving at a speed of1u2*bl6tg(pg9w7pwk3t s z itwtloui9 2:)r41e y c7uhcp5vk $3m/s$ and a pebble is moving at a speed of $5m/s$. If both objects have the same kinetic energy, what is the ratio of the brick's mass to the pebble's mass?

A. 25:9
B. 5:3
C. 4:1
D. 3:1
E. $\sqrt{5}/\sqrt{3}$


参考答案:  A


本题详细解析:
KE=$\frac{1}{2}m{v}^2$.  the mass ratio is based upon the ratio of the squares of the velocities.

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