Answer:
R = 1,746 Ω
Explanation:
The power dissipated in the circuit is
    P = V I = V² / R
Let's find the current
    R = V² / P
Let's calculate
   R = 13²/81
    R = 2,096 Ω
This is total resistance
   R_total = R + r
    R = R_total - r
    R = 2,096 -0,350
    R = 1,746 Ω
 
        
             
        
        
        
Answer:
it states that energy can neither be created or destroyed
 
        
                    
             
        
        
        
Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).
Explanation:
Kinetic energy of the hammer ,K.E.=

Half of the kinetic energy of the hammer is transformed into heat in the nail.
Energy transferred to the nail in one blow =

Total energy transferred after 3 blows,Q =
Mass of the nail = 15 g = 0.015 kg
Change in temperature =
Specif heat of the steel = c = 448 J/kg K



The increase in temperature of the nail after the three blows is 8.1  Kelvins.Hence, correct option is (d).
 
        
             
        
        
        
Ice at -25 
Hope this helps 
May God bless you and your family
        
             
        
        
        
It is required an infinite work. The additional electron will never reach the origin.
In fact, assuming the additional electron is coming from the positive direction, as it approaches x=+1.00 m it will become closer and closer to the electron located at x=+1.00 m. However, the electrostatic force between the two electrons (which is repulsive) will become infinite when the second electron reaches x=+1.00 m, because the distance d between the two electrons is zero:

So, in order for the additional electron to cross this point, it is required an infinite amount of work, which is impossible.