PLS HELP ASAP!

Priscilla is driving her car on a busy street and Harvey passes her on his motorcycle. What will happen to the sound from his mo

LiRa [457]

Answer:

the correct answer is A

Explanation:

This is a doppler effect exercise which is the change in frequency due to the relative movement of the sound source and the observer.

$f' = f_o \ \frac{v+v_o}{v-v_s}$

where v₀ is the speed of the observer and v_s the speed of the source, the signs correspond when the two are closing in

with this expression let's analyze the different answers

A) True. The observed change is in the frequency, in this case the two are moving away, so the expression that describes the phenomenon is

$f'= f_o \ \frac {v-v_o}{ v+v_s}$

In this case, the speed of the source is greater than the speed of the observer, so when the denominator increases faster than the numerator, consequently the frequency must decrease

B) False. The amplitude does not depend on the relative velocity

C) False. The intensity depends on the distance, by or which when increasing the distance the intensity should decrease

D) False. The speed of sound is a constant, if the frequency decreases the wavelength must increase to maintain equality

E) False. The speed of sound depends on the properties of the propagating medium, not on the relative speed of the source and the observer.

Consequently the correct answer is A

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3 years ago

Steel is very stiff, and the Young's modulus for steel is unusually large, 2.0×1011 N/m2. A cube of steel 25 cm on a side suppor

TEA [102]

Answer:

Force (normal) = 833.85 N Compression = 1.67 x 10⁻⁸ m

Explanation:

Given data Young's Modulus (Y) = 2 x 10¹¹ N/m², Length of one side of cube = 25 cm = 0.25 m, mass of load = 85 kg

Normal force is the force exerted upon an object that is in contact with another stable object. This force would be applied by the surface onto the object in the same vector and is used to keep the object stable while it rests on a surface.

We know from Newton's Second Law that

F = ma where m is the mass and a is the acceleration (<em>in this case due to gravity</em>) hence, the normal opposing force to the load applied by the surface would be equal to the force applied on the surface by the weight of the load on the surface, So

F (normal) = M (load) x a = 85 x 9.81 = 833.85 N

Compression is the change in length of an object by the exertion of force upon it. Using the Young's Modulus formula we can find this change in the cube of steel. The Young's Modulus is given by

Y = (F/A)/(ΔL/L), where Y is the Young's Modulus, F is the Force being applied on the object, A is the cross sectional area on which the said force is applied, ΔL is the change in length due to said force being applied and L is the original Length of the side of the cross sectional area.

Solving this for ΔL, we can re- arrange the equation

ΔL = (F x L)/(Y x A) since area of square is L x L we can simplify the equation to get

ΔL = (F)/(Y x L), substitute the values

ΔL = (833.85)/(2 x 10¹¹ x 0.25) = 1.67 x 10⁻⁸m

6 0

4 years ago

Plate Tectonics Lab: Snicker’s Science

Marizza181 [45]

Answer:

sup

Explanation:

8 0