A ball traveling at 3 m/s East hits a wall and bounces off heading West traveling at 2 m/s. If the change in direction took 0.4 second, what is the average acceleration of the ball?

A.) More information is needed
B.) 2.5 m/s^2 West
C.) 12.5 m/s^2 West
D.) 2.5 m/s^2 East
E.) 12.5 m/s^2 East

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.)