A large plate is balanced at its center and two students of equal mass stand at

Question

A large plate is balanced at its center and two students of equal mass stand at its center. The plate is rotated on a frictionless pivot about an axis through its center and perpendicular to its face. The students then begin to walk out towards opposite edges.
(Select T-True, F-False, I-Increases, D-Decreases, S-Stays the same. ).  

A) The students produce a net torque on the plate.
B) The total angular momentum of the system ... as the students walk outward.
C) The rate of rotation ... as the students walk outward.
D) The students do no work in walking outward.
E) When the students reach the edge and stop, the plate will have the same angular speed as when they started.

Explanation / Answer

(A) The students produce a net torque on the plate.(true)

Because : when the students begin to walk towards the edge, there occurs a change in the rotational velocity of the plate. Hence a net torque must be produced.

(B) The total angular momentum of the system .S(stays the same).. as the students walk outward.

Because :Angular momentum is always conserved. As per law of conservation of angular mometum.

(C) The rate of rotation .D(decreses).. as the students walk outward.

Because the mass at the axis od roration decreases and will cause decrease in rate of rotation.

D) The students do no work in walking outward. False

Because the student and the plate both exerts force on each other while walking out. Hence the force exerted for a distance will result in work done.

E) When the students reach the edge and stop, the plate will have the same angular speed as when they started.(False)

Because the plates slows down as the mass moves out

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.