Answer:

Explanation:
As we know that the magnetic field near the center of solenoid is given as

now we know that initially the length of the solenoid is L = 18 cm and N number of turns are wounded on it
So the magnetic field at the center of the solenoid is 2 mT
now we pulled the coils apart and the length of solenoid is increased as L = 21 cm
so we have

now plug in all values in it


F=mv^2/R
----> V^2=FR/m=(350x0.9)/2.5=126
----- V=11.22 m/s
No. Motion is the thing that when you're moving, you're in it.
But it IS possible for one person to say you're moving and another person to say you're not moving, both at the same time, and both of them are correct !
What uhhhhhhhhhhhhhhhhhhhhh