Complete Question
The complete question is shown on the first uploaded image 
Answer:
The work done by the spring is = 
Explanation:
Force = torque × length 
Given
 F = 9.13 N
length (L) = 5.91 cm  = 0.0591 m                         [Note 1 m = 100 cm ]
considering the formula above 
            where k denotes torque
    where k denotes torque 
           
Energy Stored  
                           
                           
  
 
        
             
        
        
        
Answer:
A)  B = 5.4 10⁻⁵ T, B) the positive side of the bar is to the West
Explanation:
A) For this exercise we must use the expression of Faraday's law for a moving body
             fem = 
             fem =  - d (B l y) / dt = - B lv
- d (B l y) / dt = - B lv
             B = 
we calculate
              B = - 7.9 10⁻⁴ /(0.73 20)
              B = 5.4 10⁻⁵ T
B) to determine which side of the bar is positive, we must use the right hand rule
the thumb points in the direction of the rod movement to the south, the magnetic field points in the horizontal direction and the rod is in the east-west direction.
Therefore the force points in the direction perpendicular to the velocity and the magnetic field is in the east direction; therefore the positive side of the bar is to the West
 
        
             
        
        
        
: the force that is necessary to keep an object moving in a curved path and that is directed inward toward the center of rotation a string on the end of which a stone is whirled about exerts centripetal<span> force on the stone — compare centrifugal force.</span>
        
             
        
        
        
Answer:
A
Explanation:
because thats what I put and got it right
 
        
             
        
        
        
Because the frictional force between the orange skin peel is great enough when you are walking for it to be carried on the tray, along with the gravitational force downwards onto the tray. When you stop, the force that you exerted moving forward it the same as on the tray and on the orange. So when you stop, the force is still on the orange as the same velocity as your we’re traveling, while the tray and you stop.