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Yuri [45]
4 years ago
9

A long stairway with a metal handrail runs between the houses of Amelia and her friend Michelle. After getting their parents' pe

rmission, the two girls often play near the stairs. One day, Michelle stands at the top of the steps and taps the railing with a stone. Amelia stands at the bottom of the steps with her right ear pressed against the railing. Amelia sees Michelle tap the railing, then she hears the sound with the ear that is pressed against the railing. Last, Amelia hears the sound with her other ear. Why did Amelia hear the sound with her right ear before her left ear?
Physics
2 answers:
Oduvanchick [21]4 years ago
7 0
Because the sound vibrations traveled faster through the solid metal and slower through the gassy air.
algol [13]4 years ago
6 0

Answer:

Sound moves faster in solids than in air. Sound sound will reach her right ear faster then on her left ear.

Explanation:

As we know that the speed of sound in solids is given by

v = \sqrt{\frac{Y}{\rho}}

also the speed of sound in air is given as

v = \sqrt{\frac{\gamma P}{\rho}}

so here we know that the Young's modulus of solid is having greater magnitude than the atmospheric pressure.

So when Amelia put her right ear on railing then sound will travel through the railing and reach the ear faster while on the other side it will reach through air.

So she will hear two sounds but she hear the sound from right ear first and then after left ear.

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An experiment is designed to investigate the relation between the pressure and temperature in a tank that has a constant volume
viva [34]

Answer:

3rd order polynomial

Explanation:

Given that the increase in the order of the polynomial the error between the curve fit and measured data will decreases hence  :

The polynomial order that is best to use is the 3rd order polynomial, this is because using a 3rd order polynomial will produce a less variance and a low Bias

4 0
3 years ago
A beam is pivoted at one end, as shown.
lara31 [8.8K]
The answer is C upwards at 20cm
7 0
3 years ago
A light-rail commuter train accelerates at a rate of 1.35 m/s2. How long does it take to reach its top speed of 80.0 km/h, start
Alona [7]

Answer:

16.46 seconds.

13.46 seconds

2.67 m/s²

Explanation:

Acceleration = a = 1.35 m/s²

Final velocity = v = 80 km/h = 80\frac{1000}{3600}=\frac{200}{9}\ m/s

Initial velocity = u = 0

Equation of motion

v=u+at\\\Rightarrow \frac{200}{9}=0+1.35t\\\Rightarrow t=\frac{\frac{200}{9}}{1.35}=16.46\ s

Time taken to accelerate to top speed is 16.46 seconds.

Acceleration = a = -1.65 m/s²

Initial velocity = u = 80 km/h= 80\frac{1000}{3600}=\frac{200}{9}\ m/s

Final velocity = v = 0

v=u+at\\\Rightarrow 0=\frac{200}{9}-1.65t\\\Rightarrow t=\frac{\frac{200}{9}}{1.65}=13.46\ s

Time taken to stop the train from top speed is 13.46 seconds

Initial velocity = u = 80 km/h= 80\frac{1000}{3600}=\frac{200}{9}\ m/s

Time taken = t = 8.3 s

Final velocity = v = 0

v=u+at\\\Rightarrow 0=\frac{200}{9}+a8.3\\\Rightarrow a=\frac{-\frac{200}{9}}{8.3}=-2.67\ m/s^2

Emergency deceleration is 2.67 m/s²

3 0
3 years ago
A 1,000 kg car is moving at 20 m/s, and slams into a building before coming to a halt.
ale4655 [162]

Hi there!

We can calculate linear momentum using the following:
\large\boxed{p = m v}

p = linear momentum (kgm/s)
m = mass (kg)
v = velocity (m/s)

Calculate:

p = 1000 * 20 = 20000 kg\frac{m}{s}

Now, we can relate force, time, and momentum with the following:
\large\boxed{I = Ft}\\\\

I = Impulse (kgm/s)
F = Force (N)
t = time (s)

Rearrange to solve for force:
F = \frac{I}{t}

The impulse is equal to the change in momentum. Since the car comes to a halt, all of its momentum is lost, so:

I = \Delta p = p_f - p_i = 0 - 20000 = -20000

Solve:
F = \frac{-20000}{0.5} = \boxed{-40000N}

**Negative force since the positive direction is towards the wall, and the negative direction is away from the wall.

7 0
3 years ago
Can anybody help me it says, Model the force that would cause each velocity change.
amid [387]

Answer:

Explanation:

Please try to take a better photo as it is difficult to read.

For the first case, it is a small force to the right as there is a small velocity change.

For the second case, there is no force as there is no change in velocity

For the third case, it is a large (could be medium but photo is too blurry) force to the right as there is a large change in velocity.

8 0
3 years ago
Read 2 more answers
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