???管外?上?????磁鐵?入塑?管中,?磁鐵?由?落,??現磁鐵?通??環中?????減速??象??/p>
如?E09漂浮磁鐵??????????近??????環?????????產??????磁?,?????要?近。當磁鐵要離?????候??環????一?吸引???磁?,?????要離??
??????
Fundamentals of Physics, Halliday
?旻?br /> ????br /> ???/p>
?昭????/p>