Answer:
Option D) 4A
Explanation:
As the cycle of the wave passes by, the amplitude gives the longest journey when the spot travels from the undistributed position. During each cycle the spot travels "Four times" .
Considering one of this cycle, if it begins to travel from it's undistributed position , there would be four movements i.e 
* Upward movement through distance A
*Downward movement through distance A
*Downward again through distance A
*Upward through distance A.
Then it would travel back to its undistributed position held
 
        
             
        
        
        
Answer:
, level is rising.
Explanation:
Since liquid water is a incompresible fluid, density can be eliminated of the equation of Mass Conservation, which is simplified as follows:


By replacing all known variables:

The positive sign of the rate of change of the tank level indicates a rising behaviour. 
 
        
             
        
        
        
Stopped at the end of the tracks by a spg-damper system, as shown in fig. 1
        
             
        
        
        
True true true true true true true true
        
                    
             
        
        
        
It will sink because it is heavier. The density of water 1.00 g/ml