Two swimmers compete in a race. under what condition do the swimmers have the same power? when one of the swimmers crosses the finish line. when both swimmers do work at the same rate. when both swimmers cover the same distance. when they do different amounts of work, but take the same time.

=force × distance a. work b. velocity c. pressure d. momentum

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in

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.)