You have a pendulum clock made from a uniform rod of mass M and length L pivoting around one end of the rod. Its frequency is 1 radian/sec. The pivot breaks. Though the mass change is negligible, you need to rehang the rod halfway between the old pivot point and the middle of the rod. The new oscillation frequency is:

unlike poles attract

i don't know that i agree with that but what's the question ?

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.