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Mila [183]
2 years ago
10

A wind turbine is rotating counterclockwise at 0.626 rev/s and slows to a stop in 12.9 s. Its blades are 17.9 m in length. What

is the centripetal acceleration of the tip of the blades at t=0~\text{s}t=0 s?
Physics
1 answer:
iogann1982 [59]2 years ago
5 0

Answer:

276.5 m/s^2

Explanation:

The initial angular velocity of the turbine is

\omega=0.626 rev/s \cdot 2\pi rad/rev =3.93 rad/s

The length of the blade is

r = 17.9 m

So the centripetal acceleration is given by

a=\omega^2 r

At the instant t = 0,

\omega=3.93 rad/s

So the centripetal acceleration of the tip of the blades is

a=(3.93 rad/s)^2 (17.9 m)=276.5 m/s^2

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A severe storm has an average peak wave height of 16.4 feet for waves hitting the shore. suppose that a storm is in progress wit
Agata [3.3K]

Before we answer this question, let us first understand what alternate hypothesis is.

The alternative hypothesis is the hypothesis which is used in the hypothesis testing and this is opposite to the null hypothesis. This is the test hypothesis which is usually taken to be that the observations are the result of a real effect in an experiment.

In this case since what we want to set up is the statistical test to see if the waves are dying down, then this means we are trying to determine if the wave height are decreasing, so lesser than 16.4 feet. Therefore:

The alternative hypothesis would state                 (ANSWER)

Ha: μ less than 16.4 feet and P-value area is on the left of the mean.

 

While the null hypothesis is the opposite and would state

H0: mu equals 16.4 feet 

4 0
3 years ago
I SERIOUSLY can't do this type of questions so can someone solve it detailedly and putting with letters (there is a system you n
KatRina [158]

Answer:

4 Ohms

Explanation

(This is seriously not as hard as it looks :)

You only need two types of calculations:

  1. replace two resistances, say, R1 and R2, connected in a series by a single one R. In this case the new R is a sum of the two: R = R_1+R_2
  2. replace two resistances that are connected in parallel. In that case: \frac{1}{R}= \frac{1}{R_1}+\frac{1}{R_2}\\\mbox{or}\\R= \frac{R_1\cdot R_2}{R_1+R_2}

I am attaching a drawing showing the process of stepwise replacement of two resistances at a time (am using rectangles to represent a resistance). The left-most image shows the starting point, just a little bit "warped" to see it better. The two resistances (6 Ohm next to each other) are in parallel and are replaced by a single resistance (3 Ohm, see formula above) in the top middle image. Next, the two resistances (9 and 3 Ohm) are nicely in series, so they can be replaced by their sum, which is what happened going to the top right image. Finally we have two resistances in parallel and they can be replaced by a single, final, resistance as shown in the bottom right image. That (4 Ohms) is the <em>equivalent resistance</em> of the original circuit.

Using these two transformations you will be able to solve step by step any  problem like this, no matter how complex.  

5 0
3 years ago
6. If a bicyclist, with initial velocity of zero, steadily gained speed until reaching a final velocity of 39m/s, how far would
Bezzdna [24]

Answer:

  175 m

Explanation:

The average velocity for constant acceleration is the average of the beginning and ending velocities. That is (0+39)/2=19.5 m/s. If the bicyclist rides for 9 seconds, the distance traveled is ...

  (9 s)(19.5 m/s) = 175.5 m

She would travel 175.5 meters in that time.

7 0
3 years ago
A runner of mass 56.0kg runs around the edge of a horizontal turntable mounted on a vertical, frictionless axis through its cent
SCORPION-xisa [38]

Answer: -0.84 rad/sec (clockwise)

Explanation:

Assuming no external torques act on the system (man + turntable), total angular momentum must be conserved:

L1 = L2

L1 = It ω + mm. v . r = 81.0 kg . m2 .21 rad/s – 56.0 kg. 3.1m/s . 3.1 m  

L1 = -521.15 kg.m2/sec (1)

(Considering to the man as a particle that is moving opposite to the rotation of  the turntable, so the sign is negative).

Once at rest, the runner is only a point mass with a given rotational inertia respect from the axis of rotation, that can be expressed as follows:

Im = m. r2 = 56.0 kg. (3.1m)2 = 538.16 kg.m2

The total angular momentum, once the runner has come to an stop, can be written as follows:

L2= (It + Im) ωf = -521.15 kg.m2/sec  

L2= (81.0 kg.m2 + 538.16 kg.m2) ωf = -521.15 kg.m2/sec  

Solving for ωf, we get:

ωf = -0.84 rad/sec  (clockwise)

5 0
2 years ago
What provides and has always provided most of Earth's energy for living things and technology?
Yakvenalex [24]
Hints:
The Earth's energy does not come from eating a balanced diet,
or from ninja turtles, or from getting sleep and exercise.
There are no hamsters running on a treadmill inside the Earth.
God didn't wind up a big spring to operate the Earth.

The Sun provides, and has always provided, almost all of the energy
used on Earth.  It was the energy that got stored in dead dinosaurs
to make gas and oil, and it's the energy that makes plants grow, and
gets stored in them so we can get the energy by eating the plants.
6 0
3 years ago
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