I got B,when you subtract 3/5 from NEGATIVE 2/3 it creates a negative 19 over a positive 15.
        
             
        
        
        
The correct option is D. 
The model developed by Ptolemy has a lot of inconsistency and during the middle age additional explanation was offered for the claims made by the model. The model was very complicated because it was based on erroneous assumptions.
Copernicus model was simpler and some of his claims were correct.<span />
        
                    
             
        
        
        
Answer: b
Explanation:
When heat is released by the system i.e. system loses heat. So, we take it as negative -Q
When the work is done on the system then it is considered as negative work on the system i.e. -W  
In this case, the plunger is pulled out, and work is done on the system. So, we take work as negative work -W
Correct option is b
 
        
                    
             
        
        
        
Answer:
weightlessness, condition experienced while in free-fall, in which the effect of gravity is canceled by the inertial (e.g., centrifugal) force resulting from orbital flight. ... Excluding spaceflight, true weightlessness can be experienced only briefly, as in an airplane following a ballistic (i.e., parabolic) path.