Which statements describe magnetic poles? Check all that apply.

1. A north pole can exist without a south pole.
2. A north pole must exist with a south pole.
3. Two south poles placed near each other will repel each other.
4. Two north poles placed near each other will attract each other.
5. A north pole and a south pole placed near each other will attract each other.
6. A south pole and a north pole placed near each other will repel each other.

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.