updatesprites.cs

            for (int i = 0; i < PhysicalSprites.Count; i++)
            {
                if (PhysicalSprites[i].IsAlive)
                    PhysicalSprites[i].Update(gameTime);
                else
                {
                    PhysicalSprites[i].Body.Dispose();
                    PhysicalSprites.RemoveAt(i);
                    i--;
                }
            }