Which is the quickest way to accurately take your heart rate

An ambulance emits a frequency of 450 hz from its siren. what frequency is heard by a man as the ambulance moves toward him? less than 450 hz more than 450 hz 450 hz 0 hz

12 drag each label to the correct category. decide whether each statement describes mass or weight. measured in newtons measured in kilograms does not change when gravity changes === a gravitational force changes when gravity changes the amount of matter in something mass weight

Describe the path of a ray that approaches a mirror parallel to the principal axis.