In (14) of section 1.3 we saw that a differential equation describing the velocity v of a falling mass subject to air resistance proportional to the instantaneous velocity is m dv dt = mg − kv, where k > 0 is a constant of proportionality. the positive direction is downward. (a) solve the equation subject to the initial condition v(0) = v0.

The magnitude of the magnetic field at a certain distance from a long, straight conductor is represented by b. what is the magnitude of the magnetic field at twice the distance from the conductor? a. at twice the distance, the magnitude of the field is 4b. b. at twice the distance, the magnitude of the field is 2b. c. at twice the distance, the magnitude of the field is b/2.d. at twice the distance, the magnitude of the field is b/4.e. at twice the distance, the magnitude of the field remains equal to b.