When a ray is directed in a mirror it reflects back with angle of incidence = angle of reflection
f' = frequency observed by the police car after sound reflected from the vehicle and comes back to police car = 1250 Hz
f = frequency emitted by the police car = 1200 Hz
V = speed of sound = 340 m/s
v = speed of vehicle = ?
frequency observed by the police car is given as
f' = f (V + v)/(V - v)
inserting the values in the above equation
1250 = 1200 (340 + v)/(340 - v)
v = 6.9 m/s
Answer:
the answer is number 2
Explanation:
because the weight of the scale is added
Hey, how's your day going.
Your answer is (should be, but I haven't done the test) A,
rock samples from the moon.
The reason why we like to test "moon rocks" is because they are undisturbed for millions of years. Were as on earth we have lots of things that could mess up our dating (wind, water, animals, geological processes, etc.) That is why you can't tell the age of the solar system from your cack yard rocks.
(My reasoning ^, not the internets!)