The Earth has a gravitational pull on a single nitrogen molecule (N2) in the air. In comparison, the gravitational pull of the nitrogen molecule on the Earth is: 1.) Weaker, but, no zero.
2.) Zero.
3.) The same size.
4.) Stronger.

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?