diff --git a/examples/ParticlesRepulsionForceField.scn b/examples/ParticlesRepulsionForceField.scn
index c5e2fee..0286eac 100644
--- a/examples/ParticlesRepulsionForceField.scn
+++ b/examples/ParticlesRepulsionForceField.scn
@@ -22,7 +22,7 @@
     <CollisionPipeline verbose="0" />
     <BruteForceBroadPhase/>
     <BVHNarrowPhase/>
-    <CollisionResponse name="Response" />
+    <CollisionResponse name="Response" response="PenalityContactForceField"/>
     <NewProximityIntersection alarmDistance="0.002" contactDistance="0.001" />
 
     <Node name="Floor">