(8th grade HELP)

A car speeding down the highway honks its horn, which has a frequency 392 Hz, but a resting bystander hears the frequency 440 Hz

Natali [406]

Answer:

37.42 m/s

Explanation:

We know that apparent frequency, $\bar f$ is given by

$\bar f=f\frac {V}{V-V_s}$ where f is the given frequency in this case 392, V is the speed of sound in air which is given as 343 and $V_s$ is the speed of car which is unknown, \bar f is given as 440 Hz

$440=392\times \frac {343}{343-V_s}\\343-V_s=392\times \frac {343}{440}=305.5818182\\V_s=343-305.5818182=37.41818182\approx 37.42 m/s$

8 0

3 years ago

1. Place these unknown pH test papers in order from most acidic to most alkaline.

Naddika [18.5K]

Answer: B

Explanation: look at the chart, easy

7 0

3 years ago

Phosphorus trichloride is used in the production of chemicals that keep plants from growing in a specific area. This compound is

Sever21 [200]

The Answer Is P should come first.

5 0

3 years ago

Read 2 more answers

Which of the following consists of several billion stars and interstellar matter?

zloy xaker [14]

The answer is galaxy

4 0

3 years ago

Read 2 more answers

A solid disk of mass 2 kg and radius 2 m is given a horizontal push of 20N at a point .3 m above its center. a. What is the mini

Margaret [11]

Answer:

$\mu_s=1.0205$

Explanation:

Given:

mass of solid disk, $m=2\ kg$

radius of disk, $r=2\ m$

force of push applied to disk, $F=20\ N$

distance of application of force from the center, $s=0.3\ m$

<em>For the condition of no slip the force of static friction must be greater than the applied force so that there is no skidding between the contact surfaces at the contact point.</em>

$\therefore F$

where:

$f_s$ = static frictional force

$\Rightarrow 20$

$\mu_s>1.0204$

7 0

3 years ago