Answer:
Wavelength=75 cm.
The wavelength well remain unchanged which is 75 cm.
Explanation:
The formula which will help us to answer the question is:
V=f*λ
Where:
V is the velocity
f is the frequency of wave
λ is the wave length
Now:
λ=V/f     Eq (1)
The equation show's that wavelength is independent of the amplitude but it depends on the frequency and the velocity with which wave is moving.
The wavelength well remain unchanged which is 75 cm.
 
        
             
        
        
        
Answer:
B. normal
please mark as brainliest
 
        
             
        
        
        
Answer:
0.71 m/s
Explanation:
We find the time it takes the stone to hit the water.
Using y = ut - 1/2gt² where y = height of bridge, u = initial speed of stone = 0 m/s, g = acceleration due to gravity = -9.8 m/s² (negative since it is directed downwards)and t = time it takes the stone to hit the water surface. 
So, substituting the values of the variables into the equation, we have
y = ut - 1/2gt² 
82.2 m = (0m/s)t - 1/2( -9.8 m/s²)t² 
82.2 m = 0 + (4.9 m/s²)t² 
82.2 m =  (4.9 m/s²)t² 
t²  = 82.2 m/4.9 m/s²
t² = 16.78 s²
t = √16.78 s²
t = 4.1 s
This is also the time it takes the raft to move from 5.04 m before the bridge to 2.13 m before the bridge. So, the distance moved by the raft in time t = 4.1 s is 5.04 m - 2.13 m = 2.91 m.
Since speed = distance/time, the raft's speed v = 2.91 m/4.1 s = 0.71 m/s
 
        
             
        
        
        
Correct one is b 
Good luck
        
                    
             
        
        
        
Observation: You saw/ observed something and you are stating that. 
Inference: You are predicting something to be true. If so and so, then this will occur.