※ 引述《andrenvq57 (喂！威，喂？)》之铭言： : [领域] (题目相关领域) : 普物 : [来源] (课本习题、考古题、参考书...) : 没解答的考古题 : [题目] : Imagine that we discover a new particle, called Q particle : by a head-on collision of two photons of energies 500 Mev and 200MeV. : The photons are annihilated in the process. : a) what is the mass of the newly discovered particle Q? : b) what is the kinetic energy of the Q particles produced in this reaction? : c) what is the momentum of the Q particles? : d) what si the velocity of the Q particles(magnitude and direction) : [瓶颈] (写写自己的想法，方便大家为你解答) : a) m = 1.24*10^-27 = 700 MeV/c^2 : b) K = 700 MeV //这我有点不确定.. : c) p = 300 MeV/c : d) 还在想... : b的部份让我很困扰，不是所有的能量都拿来形成Q了吗 : 不过能量守恒定律 K1 + K2 = Kf = 700 MeV a) 最後总能量是 500MeV+200MeV=700MeV 而动量是500-200=300MeV 所以静止质量是 2 2 1/2 (700 -300 ) =200√10 MeV b) 动能=总能-静止能量=(700-200√10)MeV c) 300MeV d) v=p/E=(300MeV)/(700MeV)=3/7倍的光速 --

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