1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Alisiya [41]
3 years ago
11

It has been argued that power plants should make use of off-peak hours to generate mechanical energy and store it until it is ne

eded during peak load times. One suggestion has been to store the energy in large flywheels spinning on nearly frictionless ball bearings. Consider a flywheel made of iron (density 7800 kg/m3 ) in the shape of a 10.0 cm thick uniform disk.
(a) What would the diameter of such a disk need to be if it is to store 10.0 megajoules of kinetic energy when spinning at 90.0 rpm about an axis perpendicular to the disk at its center?

(b) What would be the centripetal acceleration of a point on its rim when spinning at this rate?
Physics
1 answer:
sdas [7]3 years ago
3 0

Answer:

Explanation:

90 rpm = 90 / 60 rps

= 1.5 rps

= 1.5 x 2π rad /s

angular velocity of flywheel

ω = 3π rad /s

Let I be the moment of inertia of flywheel

kinetic energy = (1/2) I ω²

(1/2) I ω² = 10⁷ J

I = 2 x  10⁷ / ω²

=2 x  10⁷ / (3π)²

= 2.2538 x 10⁵ kg m²

Let radius of wheel be R

I = 1/2 M R² , M is mass of flywheel

= 1/2 πR² x t x d x R² , t is thickness , d is density of wheel .

1/2 πR⁴ x t x d = 2.2538 x 10⁵

R⁴ = 2 x 2.2538 x 10⁵ / πt d

= 4.5076 x 10⁵ / 3.14 x .1 x 7800

= 184

R= 3.683 m .

diameter = 7.366 m .

b ) centripetal accn required

= ω² R

= 9π² x 3.683

= 326.816 m /s²

You might be interested in
A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 50 cm/s. Find the rate at which th
Drupady [299]
The radius of the circle, in cm, after t seconds would be 50t 
The area, A, of the circle after t seconds is expressed in the equation: A = pi * r^2 
A = pi * (50T)^2 = pi*2500*t^2 
The change of area per unit time is obtained by differentiating the equation
A' = pi*2500*2*t A' = pi*5000*t
when t = 3 secondsA' = pi*5000*3 = 47122 cm2/s
6 0
3 years ago
Consider 2 steel rods, A and B, B has three times the area and twice the length of A, so young modulus of B will be what factor
AVprozaik [17]

Answer:

  \frac{Y}{Y_o} = 2/3

Explanation:

The yuong modulus of a rod is defined as the relationship between the tensile strength and the strain

         Y =  \frac{ \frac{F}{A} }{\frac{\Delta L}{L_o} }

let's use the subscript "o" for rod A

         I = \frac{ \frac{F}{A_o} }{ \frac{\Delta L}{L_o} }

tells us that rod B has

         A = 3 A₀

         L = 2 L₀

we substitute

         Y = \frac{ \frac{F}{A} }{ \frac{\Delta L}{L} }

          Y = \frac{ \frac{F}{3A_o} }{ \frac{\Delta L}{ 2L_o}  }

         y = ⅔  \frac{ \frac{F}{A_o}}{ \frac{\Delta }{L_o} }

substituting the value of Y₀

          Y = ⅔  Y₀

           \frac{Y}{Y_o} = 2/3

5 0
3 years ago
Suppose an electron and a proton move at the same speed. which particle has a longer de broglie wavelength? suppose an electron
BARSIC [14]
When both particles, the electron and the proton move at the same speed, they may have differences with their de Broglie wavelength, the particle that would have a longer wavelength would be the proton since the wavelength is in direct proportionality with the mass of the particle.
6 0
3 years ago
What group is Ne in? What is its period?
Gemiola [76]

Answer:

Neon (Ne), chemical element, inert gas of Group 18 (noble gases) of the periodic table, used in electric signs and fluorescent lamps. Colourless, odourless, tasteless, and lighter than air, neon gas occurs in minute quantities in Earth's atmosphere and trapped within the rocks of Earth's crust.

Explanation:

I am smart

8 0
2 years ago
Read 2 more answers
A 50kg meteorite moving at 1000 m/s strikes Earth. Assume the velocity is along the line joining Earth's center of mass and the
zysi [14]

As per the question, the mass of meteorite [ m]= 50 kg

                       The velocity of the meteorite [v] = 1000 m/s

When the meteorite falls on the ground, it will give whole of its kinetic energy to earth.

We are asked to calculate the gain in kinetic energy of earth.

The kinetic energy of meteorite is calculated as -

                                       Kinetic\ energy\ [K.E]\ =\frac{1}{2} mv^2

                                                             =\frac{1}{2}50kg*[1000\ m/s]^2

                                                               =\frac{1}{2}50* 10^{6}\ J

                                                               =25*10^6\ J    

Here, J stands for Joule which is the S.I unit of energy.

Hence,\ the\ kinetic\ energy\ gained\ by\ earth\ is\ 25*10^6\ J

4 0
3 years ago
Read 2 more answers
Other questions:
  • A cylinder shaped jar has a radius of 2 cm and a hight of 6 cm what the volume of the jar
    12·1 answer
  • A Fathom is an old depth measure equal to 6 Feet How deep in meters is a 5_ fathom deep water channel​ show working out
    8·1 answer
  • Two lasers, one red (with wavelength 633.0 nm) and the other green (with wavelength 532.0 nm), are mounted behind a 0.150-mm sli
    9·1 answer
  • Which subatomic particle will you add or remove from an atom to create a new element?
    5·1 answer
  • as you move from left to right across the electromagnetic spectrum in the image, the wavelength becomes a. longer b. lower c. sh
    13·1 answer
  • What is the most common source of energy for surface currents?
    8·2 answers
  • Compare the densities of two objects that have the same volume, but one feels heavier than the other.
    9·1 answer
  • A 10 kg bowling ball is lifted from the ground to a height of 1 meter. Assuming the bowling alley is on Earth, which type of pot
    13·1 answer
  • What are conducting patterns?
    5·1 answer
  • Determine the object of pendulum of length 90m at sea level if gravity is 10m/s​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!