In what era did the first land plants appear?

Why should galaxy collisions have been more common in the past than they are today? a. Galaxies attracted each other more strongly in the past because they were more massive; they had not yet turned most of their mass into stars. b.

What is the meaning of lightyear?

What does momentum mean?

What is the force that holds a moving object in a circular path called? Is centripetal force right?

What would be the kinetic energy of an arrow having a potential energy of 50 J after it is shot from a bow?

A skydier jumps out of a hovering helicopter so there is no forward velocity. what is the skydivers acceleration/11170085/84c6e0eb? utm_source=registration

A book of 500 leaves has a mass of 1kg if its thickness is 5cm what are the mass and thickness of each leaf

Why does a curve on a distance-time graph indicate acceleration? an increasing amount of time passes for each unit of distance a decreasing amount of time indicates a decreasing number of distance units an increasing distance is traveled during each

What would happen if you dropped two balls of different masses but equal shape and volume from a building?

A bag of sports equipment has a mass of 10.0 kilograms and a weight of