Free Body Diagram

Force Vectors  Force is a vector.  A block sliding on an inclined plane has forces acting on it.  We know there is a force of gravity and normal force. m 

Force Diagram  Draw the forces acting on the block.  The force of gravity points down with magnitude F g = mg.  The normal force points away from the surface of the inclined plane. m 

Force Diagram  Draw components of the forces so the vectors can be added.  The coordinates should point along the surface. The normal force is unknown The motion will be along the surface  The components of F g are compared to the surface. m 

Net Force  The block stays along the plane. No motion or acceleration away from the surface No force in that component  Solve for the normal force:  Net force: m 

Motion from Force  The net force causes the block to accelerate.  The amount of acceleration is force divided by mass.  This is a constant acceleration moving the block. m 

Inclined Plane  Pushing a block up an incline is easier than lifting.  To get constant velocity a force equal to the downward acceleration must be applied. m 

Mechanical Advantage  The inclined plane has been used as a machine for centuries.  Pushing a block up an incline is easier than lifting.  The ratio of the force to lift directly compared to the force using the incline is the mechanical advantage. next m 