1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
andrew-mc [135]
3 years ago
13

A police siren has a frequency of 340.0 Hz when the car is stationary and the temperature is 20°C. The police car at point S mov

es to the right with a speed of 22.0 m/s.
a. What frequency does observer A hear?
b. What frequency does observer B hear?
c. Suppose observer A is moving toward the stationary police car. What is the speed of observer A if the frequency heard is 369 Hz?

Physics
1 answer:
hodyreva [135]3 years ago
8 0

Answer:

a) 361.7 Hz

b) 318.1 Hz

c) 29.3 m/s

Explanation:

a) Speed of sound in 20 degrees celcius is 343 m/s.

Use v=wavelength*frequency to find wavelength.

343=wavelength*340

wavelegth=1.009 meters

Relative speed of waves to observer A = 343+22 = 365 m/s

Plug it back in.

365=1.009*F

F=361.7 Hz

b) Relative speed of waves to observer B = 343-22 = 321 m/s

Plug it back in.

321=1.009*F

F=318.1 Hz

c) STATIONARY CAR, so 369Hz=v/1.009. v=372.3, 372.3-343=29.3m/s!

You might be interested in
A 1000 kg car moving at 108 km/h jams on its brakes and comes to a stop. How much work was done by friction?
Nostrana [21]

Answer:

The work done by friction was -4.5\times10^{5}\ J

Explanation:

Given that,

Mass of car = 1000 kg

Initial speed of car =108 km/h =30 m/s

When the car is stop by brakes.

Then, final speed of car will be zero.

We need to calculate the work done by friction

Using formula of work done

W=\Delta KE

W=K.E_{f}-K.E_{i}

W=\dfrac{1}{2}mv_{f}^2-\dfrac{1}{2}mv_{f}^2

Put the value of m and v

W=0-\dfrac{1}{2}\times1000\times(30)^2

W=-450000
\ J

W=-4.5\times10^{5}\ J

Hence, The work done by friction was -4.5\times10^{5}\ J

3 0
3 years ago
A beaker has a mass of 125g. What is the mass of this beaker in decigrams
Anit [1.1K]
1250 decigrams
1 gram = 10 decigrams
4 0
4 years ago
Three beads are placed along a thin rod. The first bead, of mass m1 = 23 g, is placed a distance d1 = 1.1 cm from the left end o
Mila [183]

Answer:

a) x=\frac{m_{1}d_{1}+m_{2}(d_{1}+d_{2})+m_{3}(d_{1}+d_{2}+d_{3}  ) }{m_{1}+m_{2}+m_{3} }

b) x = 4.47 cm

c) x=\frac{m_{1}d_{2}+m_{2}(0)+m_{3}d_{3} }{m_{1}+m_{2}+m_{3} }

d) x = 1.48 cm

Explanation:

a) The center of mass is equal to:

x=\frac{m_{1}x_{1}+m_{2}x_{2}+m_{3}x_{3} }{m_{1}+m_{2} +m_{3}}

Where m is the mass of beads and x is the distances, if x₁ = d₁, x₂ = d₂ and x₃ = d₃

x=\frac{m_{1}d_{1}+m_{2}(d_{1}+d_{2})+m_{3}(d_{1}+d_{2}+d_{3}  ) }{m_{1}+m_{2}+m_{3} }

b) If

m₁ = 23g

m₂ = 15 g

m₃ = 58 g

d₁ = 1.1 cm

d₂ = 1.9 cm

d₃ = 3.2 cm

x=\frac{23*1.1+15*(1.1+1.9)+58(1.1+1.9+3.2) }{23+15+58 } =4.47cm

c) The center of the mass of the beads realtive to the center of bead is:

x=\frac{m_{1}d_{2}+m_{2}(0)+m_{3}d_{3} }{m_{1}+m_{2}+m_{3} }

d) x=\frac{23*(-1.9)+(15*0)+(58*3.2) }{23+15+58 } =1.48cm

6 0
3 years ago
Read 2 more answers
PLSSS HELP MEEEE
vekshin1

Answer:

Cu2+

Explanation:

7 0
3 years ago
Read 2 more answers
Determine the Mutual Inductance per unit length between two long solenoids, one inside the other, whose radii are r1 and r2 (r2
Triss [41]

Answer:

M' = μ₀n₁n₂πr₂²

Explanation:

Since r₂ < r₁ the mutual inductance M = N₂Ф₂₁/i₁ where N₂ = number of turns of solenoid 2 = n₂l where n₂ = number of turns per unit length of solenoid 2 and l = length of solenoid, Ф₂₁ = flux in solenoid 2 due to magnetic field in solenoid 1 = B₁A₂ where B₁ = magnetic field due to solenoid 1 = μ₀n₁i₁ where μ₀ = permeability of free space, n₁ = number of turns per unit length of solenoid 1 and i₁ = current in solenoid 1. A₂ = area of solenoid 2 = πr₂² where r₂ = radius of solenoid 2.

So, M = N₂Ф₂₁/i₁

substituting the values of the variables into the equation, we have

M = N₂Ф₂₁/i₁

M = N₂B₁A₂/i₁

M = n₂lμ₀n₁i₁πr₂²/i₁

M = lμ₀n₁n₂πr₂²

So, the mutual inductance per unit length is M' = M/l = μ₀n₁n₂πr₂²

M' = μ₀n₁n₂πr₂²

3 0
3 years ago
Other questions:
  • An object is released from rest at a height h. During the final second of its fall, it traverses a distance of 38m. Determine th
    5·2 answers
  • A myopic (nearsighted) lawyer has a far point of 60.0 cm. What is the diopter value of suitable corrective contacts?
    14·1 answer
  • The total negative charge on the electrons in 1kg of helium (atomic number 2, molar mass 4) is____________.
    12·2 answers
  • Water is discharged from a pipeline at a velocity v (in ft/sec) given by v = 1306p(1/2), where p is the pressure (in psi). If th
    5·1 answer
  • Given a 9.7 pF air-filled capacitor, you are asked to convert it to a capacitor that can store up to 7.7 µJ with a maximum poten
    8·1 answer
  • A simple pendulum takes 2.00 s to make one compete swing. If we now triple the length, how long will it take for one complete sw
    11·1 answer
  • A 1210 kg rollercoaster car is
    5·1 answer
  • What quantity is measured on the x-axis of a position vs. time graph.
    12·1 answer
  • What is the length of a string with a mass of 2.5 kg, with a
    12·1 answer
  • Which of the following states that energy cannot be created or destroyed?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!