The first one? If not I just guessed
        
             
        
        
        
The speed of sound at sea level is 340.29 m/s (meters per seconds).
        
             
        
        
        
Answer:
<u>We are given: </u>
initial velocity (u) = 0 m/s 
final velocity (v) = 10 m/s
displacement (s) = 20 m
acceleration (a) = a m/s/s
<u>Solving for 'a'</u>
From the third equation of motion:
v² - u² = 2as
replacing the variables
(10)² - (0)² = 2(a)(20)
100 = 40a
a = 100 / 40
a = 2.5 m/s²
 
        
             
        
        
        
Explanation:
Acceleration is the change in speed over a given time period
 
        
                    
             
        
        
        
Answer:
B. posititvely charged particles
Explanation:
Opposites attract to each other, and the same charge repels.