An 0.80-m aluminum bar is held with its length parallel to the east-west direction and dropped from a bridge. just before the bar hits the river below, its speed is 23 m/s, and the emf induced across its length is 5.5 x 10-4 v. assuming the horizontal component of the earth's magnetic field at the location of the bar points directly north, (a) determine the magnitude of the horizontal component of the earth's magnetic field.(b) state whether the east end or the west end of the bar is positive.

a)

b)  west end of the bar is positive.

Explanation:

Given:

(a)

The magnitude of the horizontal component of the Earth's magnetic field(B):

We know:

(b)

Using Fleming's left hand rule we determine that the current is flowing towards east end of the bar i.e. west end of the bar is positive.

when jerome paddle in flowing river towards east the net speed of jerome will increase

so the net speed of jerome will be given as

now the speed of paul will be same as it is given as he is running on the ground

so

so here we can say since the speed of jerome is more so he will win the race

now as we know the distance so the time difference is given as

so jerome will reach first and the time difference will be 203.55 s or 3.4 min