I believe it’s just a “v” with an arrow above it.
        
             
        
        
        
Answer:
We know the momentum after the collision MUST be equal to the momentum BEFORE the collision.  
Momentum is a VECTOR quantity having both magnitude and direction.  The first ball has momentum P =m*v = 2*4 = 8 at 90degrees.  The second ball has momentum P = 1*8 = 8 at -90 or 270 degrees.  They sum to zero when you perform vector addition.
Explanation:
 
        
             
        
        
        
The answer is D. wavelength!
        
             
        
        
        
<span>First, water evaporates from the ocean to the atmosphere, then... put each step in the correct order.
</span>Second- atmospheric circulation advects the water.
Third- water condensates to form clouds.
Fourth- precipitation falls from clouds to the land.
Fifth- some water stored as snow or ice.
Sixth- water either ±ows along the surface in rivers and lakes or infiltrates the ground.
Seventh- water returns to the ocean.