Answer:
Explanation:
Given
mass of crane 
distance moved 
Since it is moving with a constant velocity therefore net force on it is zero
Tension force=weight
T=mg
Work done by Tension T is
Work done by Gravity will be equal in magnitude but opposite in sign and can be obtained by work energy theorem which states that change in kinetic energy of object is equal to work done by all the forces
The answer to this would inFact be A
Answer: 405.3 minutes
Explanation: In order to explain this problem we have to use the following:
Fisrtly we calculate the volume of the wire, this is given by:
Vwire=π*r^2*L where r and L are the radius and L the length of teh wire, respectively.
Vwire=π*1.25*10^-3*0.26=1.27*10^-6 m^3
then the number of the total electrons in tthe wire volume is given by;
n° electrons in the wire=ρ*Vwire=8.4*10^28*1.27*10^-6 m^3=1.07 *10^23
Finally, considering the current in the wire equal to 4.4*10^18 electrons/s
the time consuming to extract all the electrons from the wire is given by:
t= total electrons in the wire/ current=1.067*10^23/4.4*10^18=24,318 s
equivalent to 405.3 minutes
They have thick body coverings
