From cac05233ffaf828adb1976f77a97851d75d8cef5 Mon Sep 17 00:00:00 2001
From: Aditya <aditya050995@gmail.com>
Date: Wed, 18 May 2022 13:26:15 -0700
Subject: [PATCH 1/2] Updated comment

Signed-off-by: Aditya <aditya050995@gmail.com>
---
 examples/worlds/linear_battery_demo.sdf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/examples/worlds/linear_battery_demo.sdf b/examples/worlds/linear_battery_demo.sdf
index b141ba3735..af5a0aa8ed 100644
--- a/examples/worlds/linear_battery_demo.sdf
+++ b/examples/worlds/linear_battery_demo.sdf
@@ -28,7 +28,7 @@
   Stop recharging the battery using a topic (optional if <recharge_by_topic> is true):
       ign topic -t /model/vehicle_blue/battery/linear_battery/recharge/stop -m ignition.msgs.Boolean -p 'data:true'
 
-  The blue vehicle should stop when it runs out of battery.
+  After the battery runs out, no force is applied to the joints in the blue vehicle. It would keep on moving as there is no friction to stop it.
   The green vehicle will not stop with recharge function.
 
 -->

From cce79a3a64c6deb53bde1e29c351438516b64da3 Mon Sep 17 00:00:00 2001
From: Aditya <aditya050995@gmail.com>
Date: Wed, 25 May 2022 16:46:30 -0700
Subject: [PATCH 2/2] Added joint friction and updated the comment

Signed-off-by: Aditya <aditya050995@gmail.com>
---
 examples/worlds/linear_battery_demo.sdf | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/examples/worlds/linear_battery_demo.sdf b/examples/worlds/linear_battery_demo.sdf
index af5a0aa8ed..fc07fe8ab7 100644
--- a/examples/worlds/linear_battery_demo.sdf
+++ b/examples/worlds/linear_battery_demo.sdf
@@ -28,7 +28,9 @@
   Stop recharging the battery using a topic (optional if <recharge_by_topic> is true):
       ign topic -t /model/vehicle_blue/battery/linear_battery/recharge/stop -m ignition.msgs.Boolean -p 'data:true'
 
-  After the battery runs out, no force is applied to the joints in the blue vehicle. It would keep on moving as there is no friction to stop it.
+  After the battery runs out, no force is applied to the joints in the blue vehicle.
+  It eventually comes to a stop due to friction in its joints. Had there been no joint friction,
+  the vehicle would have kept on moving as Gazebo currently does not support rolling friction.
   The green vehicle will not stop with recharge function.
 
 -->
@@ -434,6 +436,9 @@
         <child>left_wheel_blue</child>
         <axis>
           <xyz>0 0 1</xyz>
+          <dynamics>
+            <friction>0.2</friction>
+          </dynamics>
           <limit>
             <lower>-1.79769e+308</lower>
             <upper>1.79769e+308</upper>
@@ -446,6 +451,9 @@
         <child>right_wheel_blue</child>
         <axis>
           <xyz>0 0 1</xyz>
+          <dynamics>
+            <friction>0.2</friction>
+          </dynamics>
           <limit>
             <lower>-1.79769e+308</lower>
             <upper>1.79769e+308</upper>