Pedro is building a model motor. he would like the motor to be more powerful. which of the following would best him increase the power of the motor? a. increasing the amount of friction in the motor b. increasing the speed at which the motor does work c. decreasing the speed at which the motor does work d. reducing the amount of force that the motor produces

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.)