reviewed changes

book/force.html

@@ -1103,7 +1103,7 @@ <h1>Manipulator Control</h1>
         <li> If we push too hard (i.e. $f^{C}_{finger,z}$ is too big), then
         the pivot point will slide to the left. First, balance forces along the 
         horizontal axis to derive an upper bound for $f^{C}_{finger, z}$.
-        Then, balance forces along the y-axis an equation with $f^{C}_{finger,z}$.
+        Then, balance forces along the y-axis to obtain an equation with $f^{C}_{finger,z}$.
         Finally, combine the relations found from balancing forces in the 
         horizontal and vertical directions with  the torque lower bound from part (a) 
         to finish deriving the upper bound for the required normal force $f^{C}_{finger,z}$ 

book/force/exercises/hybrid_force_position.ipynb

@@ -389,9 +389,9 @@
    },
    "outputs": [],
    "source": [
-    "# NOTE: you may tune the velocity and duration to achieve the above specification.\n",
+    "# NOTE: We recommend the following values, though you may try different velocities and durations as well!\n",
     "velocity = -0.125  # p_des = 0.65 + velocity * max\\{time - 2.0, 0\\}\n",
-    "duration = 0.1  # duration to simulate. We check the book pose at the end of duration. set to 5~10.\n",
+    "duration = 6.5  # duration to simulate. We check the book pose at the end of duration. set to 5~10.\n",
     "log, plant, plant_context = BuildAndSimulate(compute_ctrl, velocity, duration)"
    ]
   },