Runner x starts 50 feet in front of runner z and moves with a velocity of 8.0 m/s. At what speed would runner z have to run to catch up with runner x after 2.5 s

An asteroid is discovered in a nearly circular orbit around the sun, with an orbital radius that is 2.47 times earth's. what is the asteroid's orbital period, its "year," in terms of earth years?

The necleus of an atom is made up of what subatomic particles?

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.