An induction motor is modified to allow its housing (H) and its armature (A) to rotate freely and independently about their common axis. When an alternating potential difference is applied, H and A start rotating in opposite directions, which suggests conservation of angular momentum; this is quantitatively verified by finding that no torque is required to tilt the direction of the axis of rotation. If, however, either H or A is prevented from rotating, a considerable torque is required for tilting.