added hw2 work

wjb11005 · Mar 28, 2018 · f7c244d · f7c244d
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diff --git a/HW_1_plotting.ipynb b/HW_1_plotting.ipynb
diff --git a/hw2_work/.ipynb_checkpoints/hw2_work-checkpoint.ipynb b/hw2_work/.ipynb_checkpoints/hw2_work-checkpoint.ipynb
diff --git a/hw2_work/figures/f3-6.png b/hw2_work/figures/f3-6.png
diff --git a/hw2_work/figures/pend_anim.gif b/hw2_work/figures/pend_anim.gif
diff --git a/hw2_work/figures/roller_coaster.png b/hw2_work/figures/roller_coaster.png
diff --git a/hw2_work/figures/rotating_pendulum.png b/hw2_work/figures/rotating_pendulum.png
diff --git a/hw2_work/figures/spring-mass.png b/hw2_work/figures/spring-mass.png
diff --git a/hw2_work/hw2_work.ipynb b/hw2_work/hw2_work.ipynb
diff --git a/hw2_work/octave-workspace b/hw2_work/octave-workspace
diff --git a/hw2_work/ode3.m b/hw2_work/ode3.m
@@ -0,0 +1,18 @@
+function dr=ode3(t,r,l,k,m)
+  % first order ODE for pendulum attached to 2 springs 
+  % l is pendulum length
+  % k is spring stiffness of one spring
+  % m is mass of pendulum bob
+  g=9.81;
+  dr=zeros(size(r));
+  dr(1)=r(2); % dtheta/dt=dtheta/dt
+  dr(3)=r(4); % dy/dt=dy/dt
+  if abs(r(1))<=0.2
+    dr(2)=-2*k*g/(2*k*l+m*g)*r(1);
+    dr(4)=-2*k/m*r(3);
+  else
+    ddy=1/l*1/sin(r(1))^2*[1 -cos(r(1));-l*cos(r(1)) l]*[-g*sin(r(1));-2*k/m*r(3)];
+    dr(2)=ddy(1);
+    dr(4)=ddy(2);
+end
+
diff --git a/hw2_work/ode4.m b/hw2_work/ode4.m
@@ -0,0 +1,10 @@
+function dr=ode4(t,r,k,m)
+  % first order ODEs for two masses attached by a linear spring
+  % k is spring stiffness (assume le=0)
+  % m is mass of each 
+  dr=zeros(size(r));
+    dr(1)=r(2);
+    dr(3)=r(4);
+    dr(2)=r(1).*r(4).^2-2*k/m*r(1);
+    dr(4)=-2*r(2).*r(4)./(r(1));
+end
diff --git a/intro_to_numerical_integration.ipynb b/intro_to_numerical_integration.ipynb
diff --git a/octave-workspace b/octave-workspace