Thank you for posting your question here at brainly. Below is Yoland's study:
<span>Yolanda is studying two waves. The first wave has an amplitude of 2 m, and the second has an amplitude of 3 m.
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I think the answer is "She can use constructive interference to generate a wave with an amplitude of 1.5 m."
        
                    
             
        
        
        
Answer:
Mass, m = 125 kg
Explanation:
Let us assume that the question says, "What is the mass of an object whose velocity is 400 m/s and the kinetic energy of 10⁷ J. 
The kinetic energy of an object is :

So, the mass of the object is 125 kg. 
 
        
             
        
        
        
The formula for average speed is

So we can just substitute our data.

 - its the result
 
        
        
        
Answer:
The velocity and height is 31 m/s and 44.4 m respectively .
Explanation:
Given :
Initial speed of rock , u = 8.5 m/s .
Time taken to reach ground , t = 2.25 s .
Also , acceleration due to gravity is ,  .
 . 
Now , to find the velocity when it hit ground .
Applying equation of motion :

Also , height from which rock is thrown is given by :

Hence , this is the required solution .