The left side of the armature in an electric motor is pushed down. When the current changes direction, how is the motion of the
armature affected?
It is pulled up on the left side.
It is pulled up on the right side.
It is pulled toward the commutator.
It is pushed away from the commutator

(a) assume the equation x = at^3 + bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. determine the dimensions of the constants a and b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.) (b) determine the dimensions of the derivative dx/dt = 3at^2 + b. (use the following as necessary: l and t, where l is the unit of length and t is the unit of time.)