Luster I think is what you are looking for
        
             
        
        
        
To solve this there is this website that I found that helps
I am in middle school so I have no idea how to solve this
but
this website may help considering u are in high school and u 
(hopefully mind u)
know how to solve this
so to get there u google
"whats impact speed"
and click on the first thing there the website is ehow
        
             
        
        
        
the answer is 0.284 lb/in3
 
        
             
        
        
        
The basic relationship between wavelength 

, frequency f and speed c of an electromagnetic wave is 

where c is the speed of light. Substituting numbers, we find:
