<span>Yes, the vast majority of an atom is indeed empty space. Most of it's mass is centered in the nucleus. Flying around the nucleus are the electrons, but they're very very far away (on an atomic level anyway). Most of the atom is the space between the nucleus and the electrons.</span>
        
                    
             
        
        
        
Answer: 3.49 s
Explanation:
We can solve this problem with the following equation of motion:
 (1)
 (1)
Where:
 is the final height of the ball
 is the final height of the ball
 is the initial height of the ball
 is the initial height of the ball
 is the initial velocity (the ball was dropped)
 is the initial velocity (the ball was dropped)
 is the acceleratio due gravity
 is the acceleratio due gravity
 is the time
 is the time
Isolating  :
:
 (2)
 (2)
 (3)
 (3)
Finally we find the time the ball is in the air:
 (4)
 (4)
 
        
             
        
        
        
Answer:
Tha valency of Oxygen is 2 because it need two atom of hydrogen to form water.
 
        
                    
             
        
        
        
Answer:
The magnetic field in the System is 0.095T
Explanation:
To solve the exercise it is necessary to use the concepts related to Faraday's Law, magnetic flux and ohm's law.
By Faraday's law we know that

Where,
 electromotive force
electromotive force
N = Number of loops
B = Magnetic field
A = Area
t= Time 
For Ohm's law we now that,
V = IR 
Where,
I = Current
R = Resistance
V = Voltage (Same that the electromotive force at this case) 
In this system we have that the resistance in series of coil and charge measuring device is given by,

And that the current can be expressed as function of charge and time, then

Equation Faraday's law and Ohm's law we have,



Re-arrange for Magnetic Field B, we have

Our values are given as,





Replacing,


Therefore the magnetic field in the System is 0.095T
 
        
             
        
        
        
Complete Question 
The complete question is shown on the first uploaded image 
Answer:
The velocity is    in positive x -direction
 in positive x -direction 
The speed is 
Explanation:
From the question we are told that 
 The distance from the house to truck is  D =  20 m 
   The distance traveled back to retrieve  wind-blown hat is  d =  15 
   The distance from the wind-blown hat position too the truck is  k =  20  m 
   The total time taken is  t  =  75 s 
Generally when calculating the displacement the Justin's backward movement to collect his wind - blown hat is taken as negative 
Generally Justin's displacement is mathematically represented as 
       
=>    
Generally the average velocity is mathematically represented as 
           
=>      
=>       
 
Generally the distance covered by Justin is mathematically represented as  
          
=>      
=>     
Generally Justin's average speed over a 75 s period is mathematically represented as 
             
=>         
=>        