12. the windings of a particular type of dc motor are in its rotor. the magnetic field is reversed during the rotation of the rotor by means of the
a. field magnets.
b. commutator.
c. applied power source reversal.
d. armature coil split windings.

Acentrifuge in a medical laboratory rotates at an angular speed of 3,700 rev/min. when switched off, it rotates through 54.0 revolutions before coming to rest. find the constant angular acceleration (in rad/s2) of the centrifuge. your response is within 10% of the correct value. this may be due to roundoff error, or you could have a mistake in your calculation. carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s2