3 CONTACT FORCEA FORCE THAT IS EXERTED ONLY WHEN TWO OBJECTS ARE TOUCHING.
4 CONTACT FORCEA force that is applied only when two objects are touching.
5 NONCONTACT FORCEA FORCE THAT ONE OBJECT EXERTS ON ANOTHER WHEN THEY ARE NOT TOUCHING. Noncontact forces include the gravitational force, electric force, magnetic force.
6 It is the non contact force of gravity that keeps the Moon revolving around the Earth and all of the planets revolving around the Sun.
7 Force is a vectorForce is a vector because it has size and direction. The direction is usually represented by an arrow. The unit for the size of a force is the newton (N).
8 NET FORCETHE COMBINATION OF ALL FORCES ACTING ON AN OBJECT IS CALLED THE NET FORCE N -100 N+
9 BALANCED FORCESWhen the forces acting on an object are balanced, the motion of an object does not change. Question: Can the object be moving even when the forces are balanced?+ 100 N N Net Force Equals 0 Newtons
10 BALANCED FORCESWhen the forces on an object are balanced, the motion of the object does not change. When the force of gravity acting down on a boat is equal to the buoyant force acting up on a boat, the forces are balanced and the boat floats.
11 When the upward force of air resistance is equal to the downward pull of gravity, the forces become balanced.
12 UNBALANCED FORCESWhen the net force on an object is not zero, the forces are unbalanced and the object is in motion.100 N + 25 N push friction
13 Unbalanced forces cause an object or objects to move.
14 weightWeight is the gravitational force exerted on an object. A bathroom scale measures the force of the gravitational attraction between you and the earth.
15 frictionA force that opposes the movement between two surfaces in contact.