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3 years ago

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A grinding wheel is a uniform cylinder with a radius of 8.65 cm and a mass of 0.400 kg . Calculate its moment of inertia about i

ts center.

1 answer:

anyanavicka [17]3 years ago

3 0

Answer:

I = 1.5*10⁻³ kg*m²

Explanation:

It can be showed that the moment of inertia (or rotational inertia) for a uniform cylinder of mass m and radius r, respect an longitudinal axis going through its center (parallel to the height of the cylinder) can be written as follows:

$I = \frac{1}{2}*m*r^{2} = \frac{1}{2}*0.400 kg*(0.0865m)^{2} = 1.5e-3 kg*m2$

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Find the intensity of a 55 dB sound given I 0=10^-12W/m^2

MakcuM [25]

Answer:

3.16 × $10^{-7}$ W/ $m^{2}$

Explanation:

β(dB)=10 × $log_{10}(\frac{I}{I_{0} })$

$I_{0}$ = $10^{-12}$ W/ $m^{2}$

β=55 dB

Therefore plugging into the equation the values,

55=10 $log_{10}(\frac{I}{ [tex]10^{-12}$ })[/tex]

5.5= $log_{10}(\frac{I}{ [tex]10^{-12}$ })[/tex]

$10^{5.5}$ = $\frac{I}{10^{-12} }$

316227.76× $10^{-12}$ = I

I= 3.16 × $10^{-7}$ W/ $m^{2}$

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2 years ago

How could you test the hypothesis that elephants interpreted the ground signal as being farther away than the air signal?

bekas [8.4K]

Answer:

One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.

Explanation:

This hypothesis is based on the fact that the speed of sound in air is v = 343 m / s with a small variation with temperature.

The speed of sound in solid soil is an average of the speed of its constituent media, giving values between

wood 3900 m / s

concrete 4000 m / s

fabrics 1540 m / s

earth 5000 m / s wave S

ground 7000 m / s P wave

we can see that the speed on solid earth is an order of magnitude greater than in air.

One way to test the hypothesis is to create two waves, one in the air and one on the ground at the same time. One of them for the elephant to get closer and another for the elephants to move away. Observe the reaction of the animal and with this we know which sound came first.

From the initial information, the wave going through the ground should arrive first.

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3 years ago

A soccer player takes a corner kick, lofting a stationary ball 30.0° above the horizon at 18.0 m/s. If the soccer ball has a mas

Radda [10]

Answer:

change in momentum, $\Delta p=7.65 \,kg.m.s^{-1}$

$\Delta p_x= 6.6251 \,kg.m.s^{-1}$

$\Delta p_y= 3.825 \,kg.m.s^{-1}$

Average Force, $F=144.3396\,N$

$F_x=125.0018\,N$

$F_y=72.1698\,N$

Explanation:

Given:

angle of kicking from the horizon, $\theta= 30^{\circ}$

velocity of the ball after being kicked, $v=18 m.s^{-1}$

mass of the ball, $m=0.425\, kg$

time of application of force, $t=5.3\times 10^{-2}\,s$

We know, since body is starting from the rest

$\Delta p=m.v$ .....................(1)

$\Delta p=0.425\times 18$

$\Delta p=7.65 \,kg.m.s^{-1}$

Now the components:

$\Delta p_x= 7.65\times cos 30^{\circ}$

$\Delta p_x= 6.6251 \,kg.m.s^{-1}$

similarly

$\Delta p_y= 7.65\times sin 30^{\circ}$

$\Delta p_y= 3.825 \,kg.m.s^{-1}$

also, impulse

$I=F\times t$ .........................(2)

where F is the force applied for t time.

Then from eq. (1) & (2)

$F\times t=m.v$

$F\times 5.3\times 10^{-2}= 7.65$

$F=144.3396\,N$

Now, the components

$F_x=144.3396\times cos 30^{\circ}$

$F_x=125.0018\,N$

&

$F_y=144.3396\times sin 30^{\circ}$

$F_y=72.1698\,N$

6 0

3 years ago

Read this article discussing the amount of time that people of various ages and education levels report spending on different te

iVinArrow [24]

The article is not found here but surveys are important because they are representative samples of a population.

<h3>What is a survey?</h3>

A survey is a useful tool based on population samples, which is used to make statistical analyses in a given investigation.

Differences in surveys are generally due to small sample sizes, which may lead to errors in the analysis of data.

In conclusion, the article is not found here but surveys are important because they are representative samples of a population.

Learn more about surveys here:

brainly.com/question/13624055

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1 year ago

4. A motorist travels 406 km during a 9.0 hr period. What was the average speed in km/hr and m/s?

user100 [1]

Answer:

45.11 kmph and 12.530 m/s

Explanation:

Average speed = Total distance travelled / Total time taken

406/9 gives the answer in kilometers

And we convert it to m/s by multiplying it with 1000/3600

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3 years ago