A person sits on a freely spinning lab stool that has no friction ...

[Metfan725]

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,
 
  A) her moment of inertia decreases and her angular speed increases.
  B) her moment of inertia decreases and her angular speed decreases.
  C) her moment of inertia increases and her angular speed increases.
  D) her moment of inertia increases and her angular speed decreases.
  E) her moment of inertia increases and her angular speed remains the same.

Question 2

A heat engine absorbs 85.6 kJ of heat each cycle and exhausts 61.8 kJ.
  (a) What is the efficiency of the engine?
  (b) How much work does it do each cycle?
 
  What will be an ideal response?

[Ksh22]

Answer to Question 1

D

Answer to Question 2

(a) 27.8 (b) 23.8 kJ

[Metfan725]

Thanks for the timely response, appreciate it

[Jossy]

Great answer, keep it coming