Angular Momentum and Angular Impulse AP Physics 1 MCQ – Exam Style Questions etc.
Angular Momentum and Angular Impulse AP Physics 1 MCQ
Unit 6: Energy and Momentum of Rotating Systems
Weightage : 10-15%
Exam Style Practice Questions,Angular Momentum and Angular Impulse AP Physics 1 MCQ
Question
A blue sphere and a red sphere with the same diameter are released from rest at the top of a ramp. The red sphere takes a longer time to reach the bottom of the ramp. The spheres are then rolled off a horizontal table at the same time with the same speed and fall freely to the floor. Which sphere reaches the floor first?
(A) The red sphere
(B) The blue sphere
(C) The sphere with the greater mass
(D) Neither; the spheres reach the floor at the same time.
▶️Answer/Explanation
Ans:C
Question
A friend is balancing a fork on one finger. Which of the following are correct explanations of how he accomplishes this? Select two answers.
(A) Total energy is conserved.
(B) The fork’s moment of inertia is zero.
(C) The fork’s center of mass is above his finger.
(D) The fork’s clockwise torque is equal to its counterclockwise torque.
▶️Answer/Explanation
Ans: (C) and (D)
An object’s center of mass is the balancing point by definition. The reason for this is that the moment arm on one side is the same as on the other. Therefore, the torque caused by gravity on either side will cancel.
Question
An object is experiencing a nonzero net force. Which of the following statements is most accurate?
(A) The linear and angular momentums of the object are both definitely changing.
(B) Although the linear momentum of the object is definitely changing, the angular momentum may not be.
(C) Although the angular momentum of the object is definitely changing, the linear momentum may not be.
(D) Neither the linear momentum nor the angular momentum is definitely changing.
▶️Answer/Explanation
Ans:(B)
Since \(F\Delta t=\Delta p\), net force will change the linear momentum. However, torque also involves the lever arm \((\tau=RF\sin\Theta)\). So despite having a nonzero net force, the net torque might still be zero.