The period of a wave is 20 ms (milliseconds) and its wavelength is 4 cm. Calculate: a) The frequency of the wave

b) The velocity of the wave​

Which terms describe the purpose of antennas on devices that use radio waves? transmit and receivemodify and amplifyamplify and receivemodify and transmit

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.