A Block with Mass M, on the End of a String

question 25

Multiple Choice

A block with mass M, on the end of a string, moves in a circle on a horizontal frictionless table as shown. As the string is slowly pulled through a small hole in the table:

• A) the angular momentum of M remains constant
• B) the angular momentum of M decreases
• C) the kinetic energy of M remains constant
• D) the kinetic energy of M decreases
• E) none of the above

---

Definitions:

Defense Mechanism

Psychological strategies unconsciously used to protect oneself from anxiety arising from unacceptable thoughts or feelings.

Displacement

In psychology, it's a defense mechanism where an individual shifts negative emotions or impulses from the original source to a less threatening person or object.

Ego

In psychoanalytic theory, the part of the psyche that mediates between desires, morals, and reality, playing a key role in decision making and identity.

Psychic Energy

A concept in psychoanalytic theory referring to the energy generated by the unconscious mind that can be directed into various psychological activities or behaviors.