The resistance of a given conductor depends on its electrical resistivity (
), its length(L) and its cross-sectional area (A), as follows:

In this case, we have
,
and
. So, the total resistance of the wire with length of 138m is:

Fg=m•g || IE: Weight = mass x gravity
Therefore, the relationship are as follows:
mass and gravity are inversely proportional
mass and weight are directly proportional
weight and gravity are directly proportional
Average Velocity=Total Distance/Total Time


Answer:
Actually it's 2.50 m/s, sorry
Explanation:
It is solved by using momentum conservation equation
combined mass of crow and feeder = 450+670=1120 gm
let the recoil speed of feeder be v m/s
Then applying momentum conservation we get;
1120×1.5 = 670×v
v= 2.50 m/s
the speed at which the feeder initially recoils backwards = 2.50 m/s