Choose the best description of a magnetic field line.
o
a. a magnetic field line shows the direction a positive charge would
move.
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b. magnetic field lines for a bar magnet are parallel to the magnet.
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c. magnetic field lines always point north.
o
d. a magnetic field line shows the direction a compass needle would
point.
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As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?