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katrin2010 [14]
4 years ago
14

A disk (radius = 2.00: mm) is attached to a high-speed drill at a dentist's office and is turning at 7.85 times 10^4 rad/s. Dete

rmine the tangential speed of a point on the outer edge of this disk.
Physics
1 answer:
BartSMP [9]4 years ago
3 0

Answer:

Tangential speed = 157 m/s

Explanation:

Tangential speed = Angular speed x Radius

Angular speed = 7.85 x 10⁴ rad/s

Radius = 2 mm = 2 x 10⁻³ m

Tangential speed = Angular speed x Radius = 7.85 x 10⁴ x 2 x 10⁻³

Tangential speed = 15.7 x 10 = 157 m/s

Tangential speed = 157 m/s

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The nucleus of some isotopes will spontaneously undergo nuclear decay. These isotopes are said to be radioactive. What causes th
Dmitry_Shevchenko [17]

Answer:

Here, he is able both to share his own suffering and—in a way that Mammy cannot—insist on his love for Laila. Babi's dream for leaving Afghanistan is, ironically, based in his love for the country—a love he thinks can be better kept alive by continuing to celebrate its culture and cuisine abroad.JThe nucleus of some isotopes will spontaneously undergo nuclear decay. These isotopes are said to be radioactive. What causes the nucleus of an isotope to be radioactive?

The electric force and nuclear forces are in opposition to each other

Nuclear forces disintegrate protons

There are too many electrons in its orbitals

The electric force causes electrons to be released

(please help i genuinely cant find out why)Babi had wanted Laila and Tariq to understand their country's living, breathing heritage—a heritage quite apart from the violence and turmoil of the national wars. The Buddhas, testimony to an ancient community of monks that lived in caves within the cliffs, symbolize the cultural richness of this national heritageAs an unstable atom tries to reach a stable form, energy and matter are released from the nucleus. This spontaneous change in the nucleus is called radioactive decay. When there is a change in the nucleus and one element changes into another, it is called transmutation.Carbon-14 is unstable and undergoes radioactive decay with a half-life of about 5,730 years (meaning that half of the material will be gone after 5,730 years). This decay means the amount of carbon-14 in an object serves as a clock, showing the object's age in a process called “carbon dating.”Nuclear decay occurs when the nucleus of an atom is unstable and spontaneously emits energy in the form of radiation. The result is that the nucleus changes into the nucleus of one or more other elements. These daughter nuclei have a lower mass and are more stable (lower in energy) than the parent nucleus.

7 0
2 years ago
Distance
34kurt

I honestly dont know

8 0
3 years ago
An engine draws energy from a hot reservoir with a temperature of 1250 K and exhausts energy into a cold reservoir with a temper
dimulka [17.4K]

Answer:

The power output of this engine is  P =  17.5 W

The  the maximum (Carnot) efficiency is  \eta_c  = 0.7424

The  actual efficiency of this engine is  \eta _a  = 0.46

Explanation:

From the question we are told that

    The temperature of the hot reservoir is  T_h = 1250 \ K

      The temperature of the cold reservoir  is  T_c  =  322 \ K

     The energy absorbed from the hot reservoir is E_h  = 1.37 *10^{5} \ J

       The energy exhausts into  cold reservoir is  E_c  = 7.4 *10^{4} J

The power output is mathematically represented as

      P  =  \frac{W}{t}

Where t is the time taken which we will assume to be 1 hour =  3600 s  

W is the workdone which is mathematically represented as

      W =  E_h  -E_c

substituting values

       W = 63000 J

So

    P =  \frac{63000}{3600}

    P =  17.5 W

The Carnot efficiency is mathematically represented as

          \eta_c  =  1 - \frac{T_c}{T_h}

         \eta_c  =  1 - \frac{322}{1250}

         \eta_c  = 0.7424

The actual efficiency is mathematically represented as

        \eta _a  =   \frac{W}{E_h}

substituting values

         \eta _a  =  \frac{63000}{1.37*10^{5}}

         \eta _a  = 0.46

     

7 0
4 years ago
A mass of 5kg starts from rest and pulls down vertically on a string wound around a disk-shaped, massive pulley. The mass of the
bekas [8.4K]

Answer:

1.98 m/s

Explanation:

To solve this, we would be using the law of conservation of energy, i.e total initial energy is equal to total final energy.

E(i) = E(f)

mgh = ½Iw² + ½mv²

Recall, v = wr, thus, w = v/r

Also, I = ½mr²

I = 0.5 * 5 * 2²

I = 10 kgm²

Remember,

mgh = ½Iw² + ½mv²

Substituting w for v/r, we have

mgh = ½I(v/r)² + ½mv²

Now, putting the values in the equation, we have

5 * 9.8 * 0.3 = ½ * 10 * (v/2)² + ½ * 5 * v²

14.7 = 1.25 v² + 2.5 v²

14.7 = 3.75 v²

v² = 14.7/3.75

v² = 3.92

v = √3.92

v = 1.98 m/s

Thus, the speed is 1.98 m/s

5 0
3 years ago
A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature
shepuryov [24]

You can make sure there's no change in volume by keeping
your gas in a sealed jar with no leaks.  Then you can play with
the temperature and the pressure all you want, and you'll know
that the volume is constant.

For 'ideal' gases,

       (pressure) times (volume) is proportional to (temperature).

And if volume is constant, then

                 (pressure) is proportional to (temperature) .

So if you increase the temperature from 110K to 235K,
the pressure increases to  (235/110)  of where it started.

     (400 kPa) x (235/110)  =  854.55 kPa. (rounded)

Obviously, choice-b is the right one, but
I don't know where the .46 came from.
 
4 0
3 years ago
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