Answer:
A solenoid is a type of electromagnet, the purpose of which is to generate a controlled magnetic field through a coil wound into a tightly packed helix. The coil can be arranged to produce a uniform magnetic field in a volume of space when an electric current is passed through it.
The net force on the sled is 6.6 N pointing backwards, opposite to the direction it's sliding. That's why it's slowing down, and will eventually stop.
In 60 minutes or 3600 seconds, the tip of the minute hand traverses the circumference of a circle with radius 3.00 cm, so it moves with a tangential speed of
(3.00 cm)/(3600 s) ≈ 0.00083 cm/s = 8.3 μm/s
