In order to answer the question, we need to know what was there before
AND what was there after. Is there a reason why you're concealing that
information ?
While you're at it, you might pass along the answer choices too.
Using Newton's Second Law, we can find the air resistance. We know the net force is equal to mass times acceleration.
The rule that is used to get the strength of magnetic field at the center of solenoid (B) is:
B = <span>µ x n x I where:
</span>µ is the permeability of the medium where the solenoid is based. In this problem, the medium is air which means that µ = <span>µ </span><span>o = 4 pi x 10^-7 Tm/A
</span>I is the current passing (I = 4 amperes)
n is the number of turns per unit length (5000 turns)
Substituting in the mentioned equation, we find that:
B = 4 x 3.14 x 10^-7 x 5000 x 4 = 25.132 mT