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
Klio2033 [76]
3 years ago
6

A grindstone of radius 4.0 m is initially spinning with an angular speed of 8.0 rad/s. The angular speed is then increased to 12

rad/s over the next 4.0 seconds. Assume that the angular acceleration is constant. Through how many revolutions does the grindstone turn during the 4.0-second interval?
Physics
1 answer:
PSYCHO15rus [73]3 years ago
6 0

Answer: 6.36

Explanation:

Given

Radius of grindstone, r = 4 m

Initial angular speed of grindstone, w(i) = 8 rad/s

Final angular speed of the grindstone, w(f) = 12 rad/s

Time used, t = 4 s

Angular acceleration of the grinder,

α = Δw / t

α = w(f) - w(i) / t

α = (12 - 8) / 4

α = 4/4 = 1 rad/s²

Number of complete revolution in 4s =

Δθ = w(i).t + 1/2.α.t²

Δθ = 8 * 4 + 1/2 * 1 * 4²

Δθ = 32 + 1/2 * 16

Δθ = 32 + 8

Δθ = 40 rad/s

40 rad/s = 40/2π rpm = 6.36 rpm

Therefore, the grindstone does 6.36 revolutions during the 4 s interval

You might be interested in
When a wave is acted upon by an external damping force, what happens to the energy of the wave
Rasek [7]
The energy of the wave decreases gradually
8 0
3 years ago
Read 2 more answers
A uniform electric field contains a number of particles. All are experiencing forces in the same direction as the electric field
myrzilka [38]

Answer: D

All the particles must be uncharged

Explanation:

If all the particles are positively charged, then there will be force of repulsion between them which will give different directions away from each other. The same is applicable if they are all negatively charged.

If the particles are positively and negatively charged, their will be force of attraction between them which will give different directions towards each other.

For all to be experiencing forces in the same direction, We can conclude that

All the particles must be uncharged.

8 0
3 years ago
In a thunderstorm, electric charge builds up on the water droplets or ice crystals in a cloud. Thus, the charge can be considere
muminat

Answer:

2.1\cdot 10^{21} electrons

Explanation:

The magnitude of the electric field outside an electrically charged sphere is given by the equation

E=\frac{kQ}{r^2}

where

k is the Coulomb's constant

Q is the charge stored on the sphere

r is the distance (from the centre of the sphere) at which the field is calculated

In this problem, the cloud is assumed to be a  charged sphere, so we have:

E_b=3.00\cdot 10^6 N/C is the maximum electric field strength tolerated by the air before breakdown occurs

r=1.00 km = 1000 m is the radius of the sphere

Re-arranging the equation for Q, we find the maximum charge that can be stored on the cloud:

Q=\frac{Er^2}{k}=\frac{(3.00\cdot 10^6)(1000)^2}{9\cdot 10^9}=333.3 C

Assuming that the cloud is negatively charged, then

Q=-333.3 C

And since the charge of one electron is

e=-1.6\cdot 10^{-19}C

The number of excess electrons on the cloud is

N=\frac{Q}{e}=\frac{-333.3}{-1.6\cdot 10^{-19}}=2.1\cdot 10^{21}

5 0
3 years ago
Which of the following modifications to a solenoid would be most likely to decrease the strength of its magnetic field?
Goryan [66]

By reading the fine details of the question, carefully and analytically, I have determined that there's no list of modifications to choose from.

The strength of the magnetic field of a solenoid depends on the electric current in its coil windings, the number of wire turns in its coil windings, and the material in its core.

In order to <em>DE</em>crease the strength of its magnetic field, any one or more of these steps could do the job:

-- DEcrease the electric current in its coil windings.  This can be accomplished by decreasing the voltage of the power source that energizes the coil, and/or increasing the resistance of the wire in the coil.

-- DEcrease the number of wire turns in the coil.

-- If the solenoid has anything in its core, change the core to something with a lower magnetic 'permeability'.  An Iron core will produce the greatest magnetic field strength.  Air, vacuum, or NO core will produce the lowest magnetic field strength.

8 0
3 years ago
Balances are used to measure what a. Mass of an object b. Volume c. Force acting upon it d. Level surfaces on the table
suter [353]
<span>a. Mass of an object </span>
4 0
3 years ago
Other questions:
  • It is believed that during the late Cretaceous period sea levels rose drastically resulting in about a third of the Earth's pres
    9·2 answers
  • What is the velocity of a rocket that goes 700 km north in 25 seconds?
    13·1 answer
  • He lower the frequency of the wave the ____________ it will have.
    13·1 answer
  • A train travels 98 kilometers in 1 hours, and then 78 kilometers in 3 hours. what is its average speed?
    14·1 answer
  • How far is tau hercules in light years from earth?
    15·1 answer
  • What is the magnitude of the emf induced in the secondary winding at the instant that the current in the solenoid is 3.2 A
    15·1 answer
  • Which of the following is NOT an example of environmental sustainability practices? Question 4 options: A. Waste management B. S
    7·1 answer
  • carmen and harry pack 12 cans of food into a box. five of the cans contain vegetables. seven of the cans contain soup. if harry
    7·1 answer
  • How fast can a human go before they reach terminal velocity?​
    13·1 answer
  • Elizabeth .........................................................................
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!