You happen to live on the same street as the grocery store. For a trip by car from your home to the grocery store, justify the selection of data needed to specify the average speed of your trip.
A. Displacement and Time
B. Velocity and Time
C. Distance and Time
D. Displacement and Distance

Certain bacteria (such as aquaspirillum magnetotacticum) tend to swim toward the earth’s geographic north pole because they contain tiny particles, called magnetosomes, that are sensitive to a magnetic field. if a transmission line carrying 100 a is laid underwater, at what range of distances would the magnetic field from this line be great enough to interfere with the migration of these bacteria? (assume that a field less than 5% of the earth’s field would have little effect on the bacteria. take the earth’s field to be 5.0 * 10-5 t, and ignore the effects of the seawater.)