Answer:
The vertical velocity of the skater upon landing is 10.788 meters per second.
Explanation:
Skateboarder experiments a parabolic movement. As skateboarder jumps horizontally off the top of the staircase, it means that vertical component of initial velocity is zero and accelerates by gravity, the final vertical speed is calculated by the following expression:

Where:
 - Initial vertical speed, measured in meters per second.
 - Initial vertical speed, measured in meters per second.
 - Final vertical speed, measured in meters per second.
 - Final vertical speed, measured in meters per second.
 - Gravitational acceleration, measured in meters per square second.
 - Gravitational acceleration, measured in meters per square second.
 - Time, measured in seconds.
 - Time, measured in seconds.
Given that  ,
,  and
 and  , the final velocity of the skater upon landing is:
, the final velocity of the skater upon landing is:


The vertical velocity of the skater upon landing is 10.788 meters per second.
 
        
             
        
        
        
The test tube that first stops in bubbling or the production of a gas is the tube that contains the catalyst since the reaction ended faster than the others. A catalyst is known to speed up a reaction so it must the situation aforementioned is the answer.
        
                    
             
        
        
        
Here are many things that exist as liquid at "normal" Earth temperatures. I would bet that you've seen a demonstration or someone use something with liquid mercury. 
<span>FALSE </span>
<span>Hope this helps.</span>
        
             
        
        
        
Hi there! :D
Which scientist was the first to propose the heliocentric model of the universe
