JFK's Choate Physics Laboratory Worksheet signed John F Kennedy dated March 14: One page double-sided, answering 10 questions for a laboratory experiment incorporating a DC electric motor, circa 1935. Extremely rare and revealing as to JFK's understanding and grasp of a difficult subject. Unique.
A few of the questions and JFK's responses:
3. Do the poles change and, if so, when? "They change as shown by compass needles. Attraction and repulsion when armature has moved slightly past the magnetic lines."
5. What causes motion in this case? "Attraction & Repulsion"
8. What happens? "The motor rotates clockwise."
9. Remove one and then two of the cells from the battery and notice what happens? "The contact becomes weaker causing slowing rotation."
From The Paloger Collection of John F. Kennedy Memorabilia, Historic Photographs & Original Negatives.