def act(environment)
    elapsed_time = @clock.elapsed_time
    environment.objects.each do |object|
      #Push on object.
      object.vector += Vector.new(@vector.speed * elapsed_time, @vector.pitch)
    end
  end
def act(environment)
    elapsed_time = @clock.elapsed_time
    environment.objects.each do |object|
      #Push on object.
      object.vector += Vector.new(@vector.speed * elapsed_time, @vector.pitch)
    end
  end
Add the given vector to each object, but limited by elapsed time.