8.854 m/s is the speed of the box after it reaches bottom of the ramp.
<u>Explanation</u>:
From the figure we came to know that height of the block is 4 m.
We know that,
Total "initial energy of an object" = Total "final energy of an object
"
Total "initial energy of an object" is = "sum of potential energy" and "kinetic energy" of an object at its initial position.


Initial velocity is “0” as the object does not have starting speed


Total initial energy = 39.2 × m




Now,  Total initial energy of an object = Total final energy of an object





Final speed is 8.854 m/s.
 
        
             
        
        
        
Answer:
6.6 N
Explanation:
Let's take the direction of the force of 4.0 N as positive x-direction. This means that the force of 3.0 N is at 40 degrees above it. So the components of the two forces along the x- and y-directions are:


So the resultant has components

So the magnitude of the resultant is

And in order for the body to be balanced, the third force must be equal and opposite (in direction) to this force: so, the magnitude of the third force must be 6.6 N.
 
        
             
        
        
        
Answer:
90 degrees
Explanation:
the answer is 90 because angle a has a square on the angle which means it is 90 degrees
 
        
                    
             
        
        
        
The one that will change the velocity of a periodic wave is : 
B. Changing the medium of the wave
Waves is always determined by the properties of the medium, which means that changing the medium will change the velocity of the wave
hope this helps
        
                    
             
        
        
        
Answer:
the less shielding of electrons