B
Assume north and east as two sides of a right angled triangle. magnitude of the distance is then given by the length of the hypotenuse which is 
where a = 1.2 km north
and b = 1.6 km east
magnitude = 2 km
Direction is given by the angle between them, that is atan(a/b) = 36.86 deg north of east = 53.1 deg east of north.
Answer:
a) the distance between her and the wall is 13 m
b) the period of her up-and-down motion is 6.5 s
Explanation:
Given the data in the question;
wavelength λ = 26 m
velocity v = 4.0 m/s
a) How far from the wall is she?
Now, The first antinode is formed at a distance λ/2 from the wall, since the separation distance between the person and wall is;
x = λ/2
we substitute
x = 26 m / 2
x = 13 m
Therefore, the distance between her and the wall is 13 m
b) What is the period of her up-and-down motion?
we know that the relationship between frequency, wavelength and wave speed is;
v = fλ
hence, f = v/λ
we also know that frequency is expressed as the reciprocal of the time period;
f = 1/T
Hence
1/T = v/λ
solve for T
Tv = λ
T = λ/v
we substitute
T = 26 m / 4 m/s
T = 6.5 s
Therefore, the period of her up-and-down motion is 6.5 s
Answer:
D.amplifying sound vibrations from the eardrum
this is correct
Answer: The fundamental frequency of the slinky = 8Hz
An input frequency of 28 Hz will not create a standing wave
Explanation:
Let Fo = fundamental frequency
At third harmonic,
F = 3Fo
If F = 24Hz
24 = 3Fo
Fo = 24/3 = 8Hz
If an input frequency = 28 Hz at 3rd harmonic
Let find the fundamental frequency
28 = 3Fo
Fo = 28/3
Fo = 9.33333Hz
Since Fo isn't a whole number, it can't create a standing wave
Take 320 and divide by 8
320/8 = 40 mi/hr or A
