[单选题]
A student sits on a chair that is fre
8;0 .htf wlsb3 f7tipce to move. Th
u.7ocs g:5l qd*d1 k ukje-tj-e student holds a rotating wheel as shown in the diagram.
k *tj1. cugo-:7qklsd-5eu jd
From the student’s perspective, the wheel rotates clockwise. Both the student and the chair are at rest.
The student inverted the direction of rotation of the wheel such that it is now turning clockwise according to their perspective.
Which of the following is correct about both the student and the chair system?
A. It remains at rest to keep the total momentum zero.
B. It rotates clockwise such that the total momentum is clockwise.
C. It rotates counterclockwise such that the total momentum is clockwise.
D. It rotates clockwise such that the total momentum is anticlockwise.
参考答案:
B
本题详细解析:
Explanation:
The initial total angular momentum is only that of the rotating wheel which is in the clockwise direction.
Due to conservation of angular momentum, the total initial momentum must be equal to the total final momentum.
Because the rotation of the wheel changes to anticlockwise and the total momentum of the system must still be clockwise, this means that the student and the chair rotate clockwise such that clockwise angular momentum of the student and chair is larger than the anticlockwise momentum of the wheel.
