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FrozenT [24]
3 years ago
5

You are standing at a subway platform when a subway passes, sounding its whistle. If you observe the whistle to be at 12750Hz wh

en it is approaching you and at 10750Hz after it passes,
Physics
1 answer:
adell [148]3 years ago
5 0

As per doppler's Effect of sound we can say when subway is approaching the platform we will have

f_1 = f_o* \frac{v}{v- v_s}

12750 = f_o* \frac{340}{340 - v_s}

Similarly we can find the frequency when subway is passing away with same speed from us

f_2 = f_o* \frac{v}{v + v_s}

10750 * f_o* \frac{340}{340 + v_s}

now we can find the ratio of two

\frac{12750}{10750} = \frac{340 + v_s}{340 - v_s}

1.186*(340 - v_s) = 340 + v_s

403.26 - 1.186 v_s = 340 + v_s

63.26 = 2.186 v_s

v_s = \frac{63.26}{2.186}

v_s = 28.94 m/s

So the speed of subway is 28.94 m/s

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Answer:

Carla

Explination: As Daniel's ball is dropped from the car moving at 40 mph in a horizontal direction, at the time the ball is dropped it is also moving at 40 mph in a horizontal direction due to inertia, a property of mass causing resistance to change, Daniel's ball will continue to move in a horizontal direction even after being dropped along with falling due to gravity. Daniel's ball will then fall in a projectile motion curve of sorts which will cause an overall velocity to not be straight down causing it not to fall to the ground as quickly as Carla's ball.

Sorry for the long explanation

8 0
3 years ago
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It is known that the kinetics of recrystallization for some alloy obeys the Avrami equation, andthat the value of n in the expon
trapecia [35]

Answer:8.76\times 10^{-3} min^{-1}

Explanation:

Given

n=5

0.3 fraction recrystallize after 100 min

According to Avrami equation

y=1-e^{-kt^n}

where y=fraction Transformed

k=constant

t=time

0.3=1-e^{-k(100)^5}

e^{-k(100)^5} =0.7

Taking log both sides

-k\cdot (10^{10}=\ln 0.7

k=3.566\times 10^{-11}

At this Point we want to compute t_{0.5}\ i.e.\ y=0.5

0.5=1-e^{-kt^n}

0.5=e^{-kt^n}

0.5=e^{-3.566\times 10^{-11}\cdot (t)^5}

taking log both sides

\ln 0.5=-3.566\times 10^{-11}\cdot (t)^5

t^5=1.943\times 10^{10}

t=114.2 min

Rate of Re crystallization at this temperature

t^{-1}=8.76\times 10^{-3} min^{-1}

3 0
3 years ago
The three main types of nuclear radiation are alpha, beta, and gamma
valkas [14]

Answer:

Gamma beta alpha

Explanation:

6 0
3 years ago
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A 24 kg crate is moving at a constant speed because it is being pushed with a force of 53n. What would be the coefficient of kin
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Answer:

The coefficient of kinetic friction between the crate and the floor can be calculated using the formula μ = Ff / N, where Ff is the frictional force, N is the normal force, and μ is the coefficient of kinetic friction.

In this case, the normal force is equal to the weight of the crate, which is 24 kg * 9.8 m/s2 = 235.2 N. The frictional force can be calculated using the formula Ff = μ * N, where μ is the coefficient of kinetic friction and N is the normal force.

If we substitute the values for N and Ff into the formula for the coefficient of kinetic friction, we get:μ = 53 N / 235.2 N = 0.225

Therefore, the coefficient of kinetic friction between the crate and the floor is 0.225.

6 0
1 year ago
The horn on a fire truck sounds at a pitch of 350 hz a. what is the perceived frequency when the fire truck is moving toward you
solong [7]

The perceived frequency when the fire truck is moving toward you and away from you will be 370 Hz and 329.59 Hz respectively.

<h3>What is the Doppler effect?</h3>

A sudden change in the frequency due to the distance between the objects and source is explained by the doppler effect.

As the source and observer travel toward each other, the frequency of sound, light, or other waves increases or decreases.

The perceived frequency when the fire truck is moving toward you;

\rm r' = (\frac{v+v_0}{v}) V \\\\ \rm r' = (\frac{343+20}{343}) 350 \\\\ r' =370.4  \  Hz

The perceived frequency when the fire truck is moving away from you;

\rm r' = (\frac{v-v_0}{v}) V \\\\ \rm r' = (\frac{343-20}{343}) 343 \\\\ r' =329.59  \  Hz

Hence, the perceived frequency when the fire truck in cases 1 and 2 will be 370 Hz and 329.59 Hz.

To learn more about the doppler effect refer to the link;

brainly.com/question/15318474

#SPJ1

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