Two trains travel from New Orleans to Memphis in 5 h. The first train travels at a constant velocity of 80 mph, but the velocity of the second train varies. What was the second train's average velocity during the trip

Explanation:

The first train travels at a constant velocity of 80 mph and it takes 5 h to cover the  distance so distance between two station = 80 x 5 = 400 m

second train too takes 5 h to cover the same distance so its average velocity

= total distance / total time

= 400 / 5 = 80 m /h

average velocity = 80 m /h

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

see earlier answer