What is the force, in units of millinewtons (mn), exerted on a wire that carries a current of 4.7 a when there is 3.5 cm of the wire in the magnetic field of strength 0.97 t and the wire is perpendicular to the direction of the magnetic field?

160 mN

Explanation:

The force exerted on the wire is given by

where

B is the magnetic field strength

I is the current in the wire

L is the length of the piece of wire

is the angle between the direction of the field and the wire

In this problem:

B = 0.97 T

I = 4.7 A

L = 3.5 cm = 0.035 m

Therefore, the force exerted on the wire is

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

because growing process had stoped after 4-5 year