What is the magnitude of the vector described below 15 ft/s down

Ineed the answers for these promblems i have

How are positive ions different from neutral atoms

1which body contains the majority of the mass in the solar system earth jupiter the moon the sun 2 what keeps the objects in the solar system such as planets orbiting around the sun the force of gravity the galaxy exerts on all objects within it including the solar system the great distance between the sun and the planets the sun's nuclear fusion which acts on each object the gravitational force between the sun and each object in the solar system