Ask question

Ask question

All categories

4 years ago

5

A baseball hits a car, breaking its window and triggering its alarm which sounds at a frequency of 1210 Hz. What frequency (in H

z) is heard by a boy on a bicycle riding away from the car at 8.25 m/s? Take the speed of sound to be 343 m/s.

1 answer:

IRINA_888 [86]4 years ago

8 0

Answer:

The frequency of sound heard by the boy is 1181 Hz.

Explanation:

Given that,

Frequency of sound from alarm $f_{0} = 1210\ Hz$

Speed = -8.25 m/s

Negative sign show the boy riding away from the car

Speed of sound = 343

We need to calculate the heard frequency

Using formula of frequency

$f = f_{0}(\dfrac{v+v_{0}}{v-v_{s}})$

Where, $f_{0}$ = frequency of source

$v_{0}$ = speed of observer

$v_{s}$ = speed of source

$v$ = speed of sound

Put the value into the formula

$f=1210\times\dfrac{343+(-8.25)}{343-0}$

here, source is at rest

$f=1180.8\ Hz$

$f=1181\ Hz$

Hence, The frequency of sound heard by the boy is 1181 Hz.

You might be interested in

A hiker yells out "Hello!" into a canyon. If the echo of their voice

Tasya [4]

D 193 is the right answer if not try c because it is in between them both

3 0

3 years ago

Which of the following statements is correct.

tekilochka [14]

The answer is C, as the frequency gets higher the wavelength gets shorter

6 0

3 years ago

The graph shows a wave that oscillates with a frequency of 60 Hz. Based on the information given in the diagram, what is the spe

Snezhnost [94]

Answer:

900 cm/s or 9 m/s.

Explanation:

Data obtained from the question include the following:

Length (L) = 30 cm

frequency (f) = 60 Hz

Velocity (v) =.?

Next, we shall determine the wavelength (λ).

This is illustrated below:

Since the wave have 4 node, the wavelength of the wave will be:

λ = 2L/4

Length (L) = 30 cm

wavelength (λ) =.?

λ = 2L/4

λ = 2×30/4

λ = 60/4

λ = 15 cm

Therefore, the wavelength (λ) is 15 cm

Now, we can obtain the speed of the wave as follow:

wavelength (λ) = 15 cm

frequency (f) = 60 Hz

Velocity (v) =.?

v = λf

v = 15 × 60

v = 900 cm/s

Thus, converting 900 cm/s to m/s

We have:

100 cm/s = 1 m/s

900 cm/s = 900/100 = 9 m/s

Therefore, the speed of the wave is 900 cm/s or 9 m/s.

5 0

3 years ago

A mountain climber stands at the top of a 50.0 m cliff hanging over a calm pool of water. The climber throws two stones vertical

Sonbull [250]

Answer:

a. $t=2.997\ s$ is the time after which the two stone hit the water surface.

b. $u_2=1.998\ m.s^{-1}$

c. $v_1=31.3688\ m.s^{-1}$ & $v_2=31.3686\ m.s^{-1}$

Explanation:

Given:

height of the cliff, $h=50\ m$

time gap between the projection of stones, $\Delta t=1\ s$

initial velocity of first stone, $u_1=+2\ m.s^{-1}$

Here positive sign means that the stone is thrown vertically downward in the direction of gravity.

a.

Using equation of motion:

$h=u_1.t+\frac{1}{2} g.t^2$

$50=2t+4.9t^2$

$t=2.997\ s$ is the time after which the two stone hit the water surface.

b.

using the equation of motion for second stone:

$h=u_2.t+\frac{1}{2} g.t^2$

$50=u_2\times 2.997+4.9\times 2.997^2$

$u_2=1.998\ m.s^{-1}$

c.

Final velocity of the stone at the instant of touching the water surface:

$v_1^2=u_1^2+2.g.h$

$v_1^2=2^2+2\times 9.8\times50$

$v_1=31.3688\ m.s^{-1}$

&

$v_2^2=u_2^2+2g.h$

$v_2^2=1.998^2+2\times 9.8\times 50$

$v_2=31.3686\ m.s^{-1}$

6 0

4 years ago

Describe a situation in which gravity causes a change in velocity

Katarina [22]

That's what happens whenever anything is dropped or falls.
-- a roller coaster leaves the top of a hill
-- a pencil rolls off the desk
-- the cat jumps off the top of the refrigerator
-- the little boy slides down the slide

5 0

4 years ago