Analyzing Ideas A friend claims to have built a motor by attaching a shaft to the core of a galva-
nometer and removing the spring. Can this motor
rotate through a full rotation? Explain your answer.

Yes, the magnet force will cause the motor rotate through a full rotation. So the friend who claims to have built a motor by attaching a shaft to the core of a galvanometer and removing the spring is correct.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba