Finding Net Force when there are
other forces
You must draw a Free Body
Diagram to find the Net Force.
A Free Body Diagram is a diagram where the
force vectors acting on a body are drawn and
illustrate the direction each one acts. It then
allows the net force to be found by summing
those force vectors.
FBD
Force that can act on a body:
Weight: Fgrav
Normal Force : Fnorm
Applied Force : Fapp
Friction : Ffric
Tension : Ften
Resulting force on a Body:
Net Force : Fnet
FBD Rules
1. All bodies are to be represented by shapes.
2. A force vector drawn must have the magnitude drawn to
scale in relation to any other vectors drawn.
3. All force vectors are drawn with the tail of the vector on
the body of the object and pointing in the direction it acts.
Draw the FBD for a Book sitting on the desk in the
front of the room.
Fnorm
Fgrav
Draw the FBD for Steve hanging from a string.