diff --git a/trick_source/trick_utils/SAIntegrator/examples/CannonBall/CannonBall.cpp b/trick_source/trick_utils/SAIntegrator/examples/CannonBall/CannonBall.cpp
index a896b8a3..0210aad6 100644
--- a/trick_source/trick_utils/SAIntegrator/examples/CannonBall/CannonBall.cpp
+++ b/trick_source/trick_utils/SAIntegrator/examples/CannonBall/CannonBall.cpp
@@ -6,23 +6,26 @@
 struct Cannon {
     double pos[2];
     double vel[2];
-    double acc[2];
+    Cannon(double px, double py, double vx, double vy);
 };
-void init_state ( Cannon& cannon ) {
-    cannon.pos[0] = 0.0;
-    cannon.pos[1] = 0.0;
-    cannon.vel[0] = 50.0 * cos(M_PI/6.0);
-    cannon.vel[1] = 50.0 * sin(M_PI/6.0);
-    cannon.acc[0] = 0.0;
-    cannon.acc[1] = -9.81;
+Cannon::Cannon(double px, double py, double vx, double vy) {
+    pos[0] = px;
+    pos[1] = py;
+    vel[0] = vx;
+    vel[1] = vy;
+}
+void print_header() {
+    printf ("t, cannon.pos[0], cannon.pos[1], cannon.vel[0], cannon.vel[1]\n");
+}
+void print_state( double t, Cannon& cannon) {
+    printf ("%5.3f, %5.10f, %5.10f, %5.10f, %5.10f\n",
+    t, cannon.pos[0], cannon.pos[1], cannon.vel[0], cannon.vel[1]);
 }
 void calc_derivs( double t, double state[], double derivs[], void* udata) {
-    derivs[0] = state[2]; // vel_x
-    derivs[1] = state[3]; // vel_y
-    derivs[2] = state[4]; // acc_x
-    derivs[3] = state[5]; // acc_y
-    derivs[4] = 0.0;      // Zero acc rate of change
-    derivs[5] = 0.0;
+    derivs[0] = state[2];
+    derivs[1] = state[3];
+    derivs[2] =   0.0;
+    derivs[3] = -9.81;
 }
 double impact( double t, double state[], RootFinder* root_finder, void* udata) {
     double root_error = root_finder->find_roots(t, state[1]);
@@ -33,23 +36,14 @@ double impact( double t, double state[], RootFinder* root_finder, void* udata) {
     }
     return (root_error);
 }
-void print_header() {
-    printf ("t, cannon.pos[0], cannon.pos[1], cannon.vel[0], cannon.vel[1], cannon.acc[0], cannon.acc[1]\n");
-}
-void print_state( double t, Cannon& cannon) {
-    printf ("%5.3f, %5.10f, %5.10f, %5.10f, %5.10f, %5.10f, %5.10f\n",
-    t, cannon.pos[0], cannon.pos[1], cannon.vel[0], cannon.vel[1], cannon.acc[0], cannon.acc[1]);
-}
 int main ( int argc, char* argv[]) {
-    Cannon cannon;
-    double* state_var_p[6] = { &(cannon.pos[0]), &(cannon.pos[1]),
-                               &(cannon.vel[0]), &(cannon.vel[1]),
-                               &(cannon.acc[0]), &(cannon.acc[1]) };
+    Cannon cannon(0.0, 0.0, 50.0*cos(M_PI/6.0), 50.0*sin(M_PI/6.0));
+    double* state_var_p[4] = { &(cannon.pos[0]), &(cannon.pos[1]),
+                               &(cannon.vel[0]), &(cannon.vel[1]) };
+    double t  = 0.0;
     double dt = 0.01;
-    double t = 0.0;
-    SA::RK2Integrator integ(dt, 6, state_var_p, state_var_p, calc_derivs, NULL);
-    integ.add_Rootfinder(0.00000000001, Negative, &impact);
-    init_state(cannon);
+    SA::RK2Integrator integ(dt, 4, state_var_p, state_var_p, calc_derivs, NULL);
+    integ.add_Rootfinder(1.0e-10, Negative, &impact);
     print_header();
     print_state( t, cannon);
     while (t < 20.0) {
diff --git a/trick_source/trick_utils/SAIntegrator/examples/CannonBall/README.md b/trick_source/trick_utils/SAIntegrator/examples/CannonBall/README.md
index 4f63c07e..8f0cc561 100644
--- a/trick_source/trick_utils/SAIntegrator/examples/CannonBall/README.md
+++ b/trick_source/trick_utils/SAIntegrator/examples/CannonBall/README.md
@@ -1,10 +1,33 @@
 # CannonBall
 
-This is an example of using the RK2Integrator to create a simple cannon ball simulation. We also use a rootfinder with our integrator to detect contact with the ground, and bounce the cannonball.
+The CannonBall program is an example of using the SA::RK2Integrator
+to create a simple cannon ball simulation. We also use a rootfinder
+with our integrator to detect contact with the ground, and bounce
+the cannonball.
+
+For each numerical integration time-step, the simulation program prints:
+
+1. time (s)
+2. 2D position vector (m)
+3. 2D velocity vector (m/s)
+
+to ```stdout```, in Comma Separated Values (CSV) format.
+
+### Building & Running the Simulation Program
+
+Generate the results as follows:
 
 ```
 $ make
 $ ./CannonBall > cannon.csv
+```
+### Plotting the Results
+The Python script, ```plot_trajectory.py``` is provided to plot the results
+in ```cannon.csv``` using (Python) matplotlib.
+
+Plot the cannon ball trajectory as follows:
+
+```
 $ python plot_trajectory.py
 ```