Legend

 Fnet = net force m = mass a = acceleration Fg = force of gravity FN = normal force

Vector Dynamics

In vector dynamics problems, a number unbalanced forces act on an object or system; we want to fine the net force, Fnet , that results in movement in a certain direction.   These problems use concepts from vector kinematics and dynamics.   Determining a resultant force from a number of component forces (recall that force is a vector - has a size and direction), Newton's three laws of motion.

The only new tool required is free-body diagrams.   These are simple picture that show all the forces action on a particular object or system.

 Example:

From the random lessons menu, we have the pitcher throwing the baseball.

Free-body diagram for a baseball being thrown to the right:

Free-body diagram for a baseball once it is released by the pitcher:
 Example 2:
As we have mentioned in the very first basic concept of vectors, vectors can be broken down to horizontal and vertical directions.   The boy pulling the cart above is using 100 N.  The vertical force is Fsin30.0o and horizontal force is Fcos30.0o.
 Net Force Weight