2.  Gravitational force – always present between two objects that have mass. Usually not felt unless one of the objects is very large. On earth 9.81 m/s 2. Always pulls down.  Magnetic force  Electrical force

3.  Normal force : force on an object in contact with another stable object. Always perpendicular to the surfaces in contact. Weight of block Normal Force Friction Force

4.  Applied force: a force applied to one object by another.  Frictional force: The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. › Sliding friction: between moving objects › Static friction: between stationary objects › Air resistance

5.  Tension: the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends.  Spring force: exerted by a compressed or stretched spring upon any object that is attached to it.

6. Force is a vector. Force vector arrows are drawn in the direction that the force is pushing or pulling.

10. Go Zebras! Ft Fg