Describe how to make the open electric circuit with the help of objects found around you

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Awave with a frequency of 500 hz is traveling at a speed of 100 m/s. what is the wavelength?

Do you think you could give me the answers to #29?