The magnetic strips on a credit card can become demagnetized. what type of magnet are they?

Determine the maximum r-value of the polar equation r =3+3 cos 0

What are two different ways you could find the value of a? explain these methods.

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •