15 points!the doppler effect is used in police car to measure a) temperature b) weather c) speed d) reckless driving

C. Speed they used a radar gun to measure speed

The answer to this question is:
c. speed

hope this helps

They can measure  the amount of energy gained or lost

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .