erro ao compilar script

 The variable fisica of aviao has not been assigned.
You probably need to assign the fisica variable of the aviao script in the inspector.
UnityEngine.Rigidbody2D.AddForce (UnityEngine.Vector2 force, UnityEngine.ForceMode2D mode) (at <65cab14ac59e4552b77f98a4aed18f9e>:0)
aviao.Impulsionar () (at Assets/Scripts/aviao.cs:24)
aviao.Update () (at Assets/Scripts/aviao.cs:18)

alguem pode me ajudar a resolver isso??? aqui esta o script

public class aviao : MonoBehaviour{
   Rigidbody2D fisica;
   private void Aweke()
   {
          this.fisica = this.GetComponent<Rigidbody2D>();

   }


    private void Update()
    {
     if(Input.GetButtonDown("Fire1"))   
     {
     this.Impulsionar();
     }
    }

    private void Impulsionar()
    {
    this.fisica.AddForce(Vector2.up * 10, ForceMode2D.Impulse);
    }
}