Answer:
a). 
b). 
Explanation:
For the block that stays on the track, its maximal height is attained when all of the kinetic energy  is converted to potential energy
a).
The height for the block on the longer track can by find using this equation:

Cancel the mass as a factor in each element in the equation 



b). 
The other lost some kinetic energy so, use a projectile motion to determine the total height for the other bock:




Solve to v'





 
        
                    
             
        
        
        
Water vapour has more kinetic energy.
Hope this helps :)
        
                    
             
        
        
        
high velocity is the answer as baby oil is dense 
 
        
             
        
        
        
Answer:
Options A and B.
Explanation:
Gravitational acceleration, initial height, intial speed and time are required to determine final speed. The option D is incorrect, since speed varies in time. Option C is dimentionally wrong. 
The correct strategy is calculating the initial height from option B. Later, substituting time in equation A to derive an expression of the final velocity in terms of position. Hence, the required equations are options A and B.
 
        
             
        
        
        
There can be an experiment run using two or more cleansers at the same time as the manufacturers' one