If a bicycle travels 800m in a time of 72 seconds how fast is it moving

An element becomes a positively charged ion when itloses protons. loses electrons. gains electrons. gains neutrons.

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

Which of the following are molecules? a. al b. ag c. mgcl2 d. nacl e. c3h8