Answer:
Explanation:
mass of elephant, m1 = 5240 kg 
mass of ball, m2 = 0.150 kg 
initial velocity of elephant, u1 = - 4.55 m/s 
initial velocity of ball, u2 = 7.81 m/s 
Let the final velocity of ball is v2. 
Use the formula of collision 


v2 = - 16.9 m/s 
The negative sign shows that the ball bounces back towards you. 
(b) It is clear that the velocity of ball increases and hence the kinetic energy of the ball increases. This gain in energy is due to the energy from elephant. 
 
        
             
        
        
        
Complete Question 
A proton is located at <3 x 10^{-10}, -5*10^{-10}  , -5*10^{-10}> m. What is r, the vector from the origin to the location of the proton
Answer:
The  vector position is   
Explanation:
From the question we are told that 
   The  position of the proton is  
 
Generally the vector location of the proton is mathematically represented as 
        
So substituting values 
      
 
        
             
        
        
        
Interesting question. 
There are a number of factors that may attribute to the pricing of an item say quality of material, number of special features available, and certainly a common notion of brand value (e.g H&M vs GUCCI). Of course, it does not necessarily mean more face value = more expensive. 
Typically, to estimate, I would check the brand and material component. 
 
        
             
        
        
        
This is a bit too broad. Maybe this is something to google up