Find the frequency of a wave with a period of 0.5 seconds

Do you agree with scientist’s prediction about the warming of alaska and other polar regions?

In order of decreasing light-transmitting capabilities of materials, which is the correct sequence? a. transparent -> translucent -> opaque b. opaque -> transparent -> translucent c. opaque -> translucent -> transparent d. translucent -> transparent -> opaque

What happens when a rubber rod is rubbed with a piece of fur?