Quiz 1:

Class Vote:

Great result!!! Not too surprising though, I guess, as this was a masteringphysics pre-class quiz! (Correct Answer = D)

Quiz 2:

Class Vote:

Perhaps it was not stated very clearly that a and c are instants when the string is at its maximum displacement from equilibrium. For sinusoidal wave motion, you can think of every point on the string as exhibiting vertical SHM. So when an oscillator is at its maximum displacement, its instantaneous velocity is zero (turn-around point). (Correct answer = A)

Quiz 3

Class Vote:

Every part of the string exhibits vertical SHM, so when it’s at equilibrium (point b), it is moving at its maximum velocity, either up or down, depending on the location along the string. (Correct Answer = D)

Quiz 4

Class Vote:

Every part of the string exhibits vertical SHM, so when it’s at maximum displacement (point a or c), it is momentarily stopped, with zero velocity. (Correct Answer = A)

Quiz 5

Class Vote:

Every part of the string exhibits vertical SHM, so when it’s at equilibrium (point b), the net force on it is zero, and therefore its acceleration is also zero. (Correct Answer = A)