I am trying to implement `Accelerometer` in my game using `Andengine` and i also add `andenginephysicsbox2dextension.jar`

```
private PhysicsWorld mPhysicsWorld;

//--OnLoadScene()

this.mPhysicsWorld = new PhysicsWorld(new Vector2(0, SensorManager.GRAVITY_EARTH), false);

```

When i implement this line i got error and not able to run.

How to fix this error?

Logcat Errors:

```
07-27 13:57:21.125: ERROR/AndroidRuntime(1006): FATAL EXCEPTION: main
07-27 13:57:21.125: ERROR/AndroidRuntime(1006): java.lang.ExceptionInInitializerError
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at Org.Demo.PixelPerfectTest.onLoadScene(PixelPerfectTest.java:223)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at org.anddev.andengine.ui.activity.BaseGameActivity.doResume(BaseGameActivity.java:158)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at org.anddev.andengine.ui.activity.BaseGameActivity.onWindowFocusChanged(BaseGameActivity.java:82)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at com.android.internal.policy.impl.PhoneWindow$DecorView.onWindowFocusChanged(PhoneWindow.java:2152)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.view.View.dispatchWindowFocusChanged(View.java:4691)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.view.ViewGroup.dispatchWindowFocusChanged(ViewGroup.java:752)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.view.ViewRoot.handleMessage(ViewRoot.java:2102)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.os.Looper.loop(Looper.java:132)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at android.app.ActivityThread.main(ActivityThread.java:4025)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at java.lang.reflect.Method.invokeNative(Native Method)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at java.lang.reflect.Method.invoke(Method.java:491)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at dalvik.system.NativeStart.main(Native Method)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006): Caused by: java.lang.UnsatisfiedLinkError: Couldn't load andenginephysicsbox2dextension: findLibrary returned null
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at java.lang.Runtime.loadLibrary(Runtime.java:425)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at java.lang.System.loadLibrary(System.java:554)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     at org.anddev.andengine.extension.physics.box2d.PhysicsWorld.<clinit>(PhysicsWorld.java:30)
07-27 13:57:21.125: ERROR/AndroidRuntime(1006):     ... 15 more

```