Traveling-wave interaction and secondary magnetic field is generated electromagnetic force, which is a straight line to run the basic principles of electric motors.

行波磁场与次级相互作用便产生电磁推力，这就是直线电动机运行的基本原理。

youdao

Power wire in a magnetic field direction of movement of the force and the magnetic sense of direction with the current line (magnetic field) direction related.

通电导线在磁场中受力运动的方向跟电流方向和磁感线(磁场方向)方向有关。

youdao

Place any magnet under the unit and set it on an overhead projector-and you will see the filings moving to line up along the lines of magnetic force.

将一磁铁放在盒下并将它放在一投影机下面——你即可看到铁粉随著磁力线的分布而移动。

youdao

Because Jupiter's axis of rotation does not quite line up with its magnetic axis, the moons that orbit the planet feel such a fluctuating magnetic force.

ECONOMIST: Blue moon