Hey there mate :)
Even if two persons are given the same work load, the speed of the work done gets different by the energy of those persons.
No one is sure that he/she can complete the work within the time. He may or may not.
Also, the physical characteristics makes the work different. If one person has so much power to work all day, the other person may not have.
Therefore, <em>even if two persons do the same amount of work , they may have different power</em><em>.</em>
The magnetic field is described mathematically as a vector field<span>. This vector field can be plotted directly as a set of many vectors drawn on a grid. Each vector points in the direction that a compass would point and has length dependent on the strength of the magnetic force. </span>
The wire vibrates back and forth between the poles of the magnet.
The frequency of the vibration is the frequency of the AC supply.
The model bridge captures all the structural attributes of the real bridge, at a reduced scale.
Part a.
Note that volume is proportional to the cube of length. Therefore the actual bridge will have 100^3 = 10^6 times the mass of the model bridge.
Because the model bridge weighs 50 N, the real bridge weighs
(50 N)*10^6 = 50 MN.
Part b.
The model bridge matches the structural characteristics of the actual bridge.
Therefore the real bridge will not sag either.