What is the wavelength of a microwave with a frequency of 10 Hz

Idon’t quite understand this problem

If an athlete runs once around a track, back to the starting line, her average velocity is zero. true or false?

Astone weighing 1.5 kilograms is resting on a rock at a height of 20 meters above the ground. the stone rolls down 10 meters and comes to rest on a patch of moss. the gravitational potential energy of the stone on the moss is joules.