Gravitational force – the basics

Integrated ScienceForces & MotionAges 11–12

Two spheres attract each other without touching, a classic example of a non-contact force; each sphere is held back by a person standing outside and pulling on a rope. Change the masses of the two objects and drag them closer together or further apart, watch the force arrows and how far each puller leans, then tick "Show force values" to compare the readings with your prediction. Based on the "Gravity Force Lab: Basics" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: Contact and non-contact forces