Hi there!
II. Linear momentum of the system is zero. 
This is an example of a RECOIL collision. With the Law of Conservation of Momentum, momentum remains constant before and after the collision. 
Thus, the total momentum would also be equivalent to zero after the collision.
 
        
             
        
        
        
I’m sorry if i took up a lot of space, hope this is a valid approximate answer
 
        
        
        
Answer:
Work done, W = 2675.4 J
Given:
mass, m = 70.0 kg
height, H = 3.90 m
Solution:
According to the question, as the person jumps the stairs up, there is an increase in the potential energy of the person which is provided by the work done in climbing the stairs and is given by:
Work done, W = mgH
where
g = acceleration due to gravity = ![9.8 m/s^{2}[tex][tex]W = 70.0\times 9.8\times 3.90 = 2675.4 J](https://tex.z-dn.net/?f=9.8%20m%2Fs%5E%7B2%7D%5Btex%5D%3C%2Fp%3E%3Cp%3E%5Btex%5DW%20%3D%2070.0%5Ctimes%209.8%5Ctimes%203.90%20%3D%202675.4%20J)
 
        
             
        
        
        
Answer:
The value is   
        
Explanation:
From the question we are told that 
      The length of the crack is   
 
      The  frequency is   
 
       The distance outside the cave that is being consider is   
 
       The speed of sound is 
Generally the wavelength of the wave is mathematically represented as 
         
=>     
=>     
Generally for a  single slit the path difference between the interference patterns of the sound wave and the center  is mathematically represented as   
           
=>     
=>     
Generally the width of the sound beam is mathematically represented as 
          
=>      
=>      