When the motor below is connected to the battery, the iron bar and copper coil spin in a circle. If no energy is lost as heat and no electrical energy remains after it runs through the coil, how much of the electrical energy flowing through the copper wire is transformed into mechanical energy?
A.
all of it
B.
half of it
C.
none of it
D.
a tiny fraction of it

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