As the block initially moves from z =D toward r = 0, does the spring force do positive, negative, or zero work? When the block is at z = D, I slap a hunk of clay straight down (that is, with no horizontal velocity) onto the mass and it sticks. Does the amplitude of oscillation increase, decrease, or neither? What about the period of oscillation? The system is reset to t = 0. This time, I add the clay when the block passes through z = 0. Does the amplitude of oscillation increase, decrease, or neither? What about the period of oscillation?

As the block initially moves from z =D toward r = 0, does the spring force do positive, negative, or zero work? When the block is at z = D, I slap a hunk of clay straight down (that is, with no horizontal velocity) onto the mass and it sticks. Does the amplitude of oscillation increase, decrease, or neither? What about the period of oscillation? The system is reset to t = 0. This time, I add the clay when the block passes through z = 0. Does the amplitude of oscillation increase, decrease, or neither? What about the period of oscillation?