Which statement best explains why objects are pulled toward Earth's center?
Earth has a magnetic force that is strongest at its core.
Earth has a much greater mass than objects on its surface.
The weight of the atmosphere pushes objects toward Earth's surface.
The strength of the Sun's gravity pushes down on objects at Earth's surface.

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration