Physics Unit26: Special Theory of Relativity (id: a2242bed4)

[单选题]
A spear is thrown by you at a very hivq ohb1(91ncjgh speed. As it passes, you meaiy)41zj y g0sr9uj d .hkiu.j.sure its lengthzu.jk 1 y0yj)..ujii4hsd9gr at one-half its normal length. From this measurement, you conclude that the moving spear's mass must be

A. one-half its rest mass.
B. twice its rest mass.
C. four times its rest mass.
D. none of the given answers


参考答案:  B


本题详细解析: 暂无