Answer:
2653 turns
Explanation:
We are given that
Diameter,d=2 cm
Length of magnet,l=8 cm=
1m=100 cm
Magnetic field,B=0.1 T
Current,I=2.4 A
We are given that
Magnetic field of solenoid and magnetic are same and size of both solenoid and magnetic are also same.
Length of solenoid=
Magnetic field of solenoid

Using the formula

Where 

Explanation:
4a)the displacement is the distance moved in a direction but since no direction is given, the displacement is equal to the distance
b) the distance moved is 400m because that's the length of the track
Answer: Look where the points are.
Explanation: