Fix typo

Author: diarmidmackenzie

examples/physics/index-ammo.html

@@ -154,7 +154,7 @@
       <a-entity class="transformer" mixin="transformer" position = "0 1.6 -1"
                 material="src:#colortransform" shadow></a-entity>
 
-      <!-- ground collider keeps objets from falling -->
+      <!-- ground collider keeps objects from falling -->
       <a-box id= "ground" ammo-body="type: static" ammo-shape="type: box" width="100" height="0.01" depth="100" visible="false"></a-box>
       <a-link href="../mouse" title="Basic Example"
               ammo-body="type: static" ammo-shape="fit: manual; type: sphere; sphereRadius: 0.25"