V = I * R
Where V is the voltage, I is the current and R is the resistance. Using Ohm's law, you require resistance to find the current through the wire. Technically, if the wire has a resistance of 0, you will get infinite current. But this isn't possible. Maybe the negligible resistance refers to the battery's internal resistance - not the wire's resistance. 
        
             
        
        
        
Answer:
 6.4m/s
Explanation:
The total mechanical energy of the man is 1780J. 
This mechanical energy is the energy due to the motion of the body and it is a form of kinetic energy. 
  Also, mass  = 87kg 
    Kinetic energy  =  m v²
   m v²
m is the mass 
v is the velocity 
            1780  =   x 87 x v²
 x 87 x v² 
                 v²  = 40.9
                 v  = 6.4m/s