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MakcuM [25]
2 years ago
8

A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center. Rotating flywheels provid

e a means for storing energy in the form of rotational kinetic energy and are being considered as a possible alternative to batteries in electric cars. The gasoline burned in a 309-mile trip in a typical midsize car produces about 2.96 x 109 J of energy. How fast would a 10.1-kg flywheel with a radius of 0.437 m have to rotate to store this much energy? Give your answer in rev/min.
Physics
1 answer:
Kisachek [45]2 years ago
6 0

Answer:

\dot n = 748178.306\,rpm

Explanation:

A flywheel stores mechanical energy in the form of rotational kinetic energy:

K = \frac{1}{2}\cdot I \cdot \omega^{2}

The expression is simplified by considering the flywheel as a solid disk:

K = \frac{1}{4}\cdot m\cdot r^{2}\cdot \omega^{2}

The final speed of the flywheel is:

\Delta E = \frac{1}{4}\cdot m \cdot r^{2}\cdot \omega^{2}

\omega = \sqrt{\frac{4\cdot \Delta E}{m\cdot r^{2}} }

\omega = \frac{2}{r}\cdot \sqrt{\frac{\Delta E}{m} }

\omega = \frac{2}{0.437\,m}\cdot \sqrt{\frac{2.96\times 10^{9}\,J}{10.1\,kg} }

\omega \approx 78349.049\,\frac{rad}{s}

The final speed in revolutions per minute is:

\dot n = \frac{60\cdot \omega}{2\pi}

\dot n = \frac{60\cdot (78349.049\,\frac{rad}{s} )}{2\pi}

\dot n = 748178.306\,rpm

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Answer:

For the bird moving in a straight line, the kinetic energy is one-half the product of the mass and the square of the speed: Ek=12mu2.

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2 years ago
Suppose we consider the system of the three capacitors as a single "equivalent" capacitor. Given the charges of the three indivi
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8 0
2 years ago
The viewing screen in a double-slit experiment with monochromatic light. Fringe C is the central maximum. The fringe separation
makvit [3.9K]

Answer:

<em>Part A</em><em>:</em>

a) If the wavelength of the light is decreased the fringe spacing Δy will decrease.

<em>Part B</em><em>:</em>

b) If the spacing between the slits is decreased the fringe spacing Δy will increase.

<em>Part C</em><em>:</em>

a) If the distance to the screen is decreased the fringe spacing will decrease.

<em>Part D</em><em>:</em>

The dot in the center of fringe E is 920\ x\ 10^{-9} m farther from the left slit than from the right slit.

Explanation:

In the double-slit experiment there is a clear contrast between the dark and bright fringes, that indicate destructive and constructive interference respectively, in the central peak and then is less so at either side.

The position of bright fringes in the screen where the pattern is formed can be calculated with

                      \vartriangle y =\frac{m \lambda L}{d}

                      m=0,\pm 1,\pm 2,\pm 3,.....

  1. m is the order number.
  2. \lambda is the wavelength of the monochromatic light.
  3. L is the distance between the screen and the two slits.
  4. d is the distance between the slits.
  • Part A:  a) In the above equation for the position of bright fringes we can see that if the wavelength of the light \lambda is decreased the overall effect will be that the fringes are going to be closer. That means that the fringe spacing Δy will decrease.
  • Part B:  b) In the above equation for the position of bright fringes we can see that if the spacing between the slits d is decreased the fringes are going to be wider apart. That means the fringe spacing Δy will increase.
  • Part C:  a) In the above equation we can see that if the distance to the screen L is decreased the fringes are going to be closer. That means the fringe spacing Δy will decrease.
  • Part D: We are told that the central maximum is the fringe C that corresponds with m=0. That means that fringe E corresponds with the order number m=2 if we consider it to be the second maximum at the rigth of the central one. To calculate how much farther from the left slit than from the right slit is a dot located at  the center of the fringe E in the screen we use the condition for constructive interference. That says that the  path length difference Δr between rays coming from the left and right slit must be \vartriangle r=m \lambda

        We simply replace the values in that equation :

                      \vartriangle r= m \lambda =2.\ 460\ nm

                      \vartriangle r= 920\ x\ 10^{-9} m

         The dot in the center of fringe E is 920\ x\ 10^{-9}m farther from the left slit than from the right slit.

     

       

       

     

3 0
3 years ago
Landslides and mudslides can result from both volcanoes and earthquakes.<br><br> true<br> false
EleoNora [17]
The correct answer would be True!
4 0
3 years ago
A projectile is launched horizontally from a height of 8.0 m. The projectile travels 6.5 m before hitting the ground.
Effectus [21]
Time it takes the projectile to hit the ground after being thrown up:

√h/1/2a

√8/(.5)(9.81)

√8/4.905

√1.630988787

= 1.277101714

= 1. 28

hope this helps :)
7 0
2 years ago
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