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sineoko [7]
3 years ago
5

A researcher wondered whether drivers treat bicycle riders differently when they wear helmets. He rigged his bicycle with an ult

rasonic sensor that could measure how close each car was that passed him. He then rode on alternating days with and without a helmet. Of the 30003000 times that a car passed​ him, he found that when he wore his​ helmet, motorists passed 3.273.27 inches closer to​ him, on​ average, than when his head was bare. What is the WhoWho in this​ study? That​ is, identify the cases under study.
A. The bike riders
B. Each instance of a car passing a rider
C. Bike helmets
D. The cars
Mathematics
1 answer:
andrew-mc [135]3 years ago
3 0

Answer:

In this case study we have following groups:

1. Population: It had all the cars which passed the bicyclist. Out of which 3000 cars were taken.

2. Who:  Each instance of a car passing a rider, means the drivers passing by.

That is the 3000 cars which passed the researcher on his bicycle.

3. What: The distance at which cars pass the bicycle rider. The distance the drivers stayed away from his bike.

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What is the quantity proportional to 18/6
mario62 [17]

Answer:

18/6=3

Step-by-step explanation:

18/6÷3=6/2

6/2=3

7 0
3 years ago
Evaluate the surface integral S F · dS for the given vector field F and the oriented surface S. In other words, find the flux of
Tomtit [17]

Apparently my answer was unclear the first time?

The flux of <em>F</em> across <em>S</em> is given by the surface integral,

\displaystyle\iint_S\mathbf F\cdot\mathrm d\mathbf S

Parameterize <em>S</em> by the vector-valued function <em>r</em>(<em>u</em>, <em>v</em>) defined by

\mathbf r(u,v)=7\cos u\sin v\,\mathbf i+7\sin u\sin v\,\mathbf j+7\cos v\,\mathbf k

with 0 ≤ <em>u</em> ≤ π/2 and 0 ≤ <em>v</em> ≤ π/2. Then the surface element is

d<em>S</em> = <em>n</em> • d<em>S</em>

where <em>n</em> is the normal vector to the surface. Take it to be

\mathbf n=\dfrac{\frac{\partial\mathbf r}{\partial v}\times\frac{\partial\mathbf r}{\partial u}}{\left\|\frac{\partial\mathbf r}{\partial v}\times\frac{\partial\mathbf r}{\partial u}\right\|}

The surface element reduces to

\mathrm d\mathbf S=\mathbf n\,\mathrm dS=\mathbf n\left\|\dfrac{\partial\mathbf r}{\partial u}\times\dfrac{\partial\mathbf r}{\partial v}\right\|\,\mathrm du\,\mathrm dv

\implies\mathbf n\,\mathrm dS=-49(\cos u\sin^2v\,\mathbf i+\sin u\sin^2v\,\mathbf j+\cos v\sin v\,\mathbf k)\,\mathrm du\,\mathrm dv

so that it points toward the origin at any point on <em>S</em>.

Then the integral with respect to <em>u</em> and <em>v</em> is

\displaystyle\iint_S\mathbf F\cdot\mathrm d\mathbf S=\int_0^{\pi/2}\int_0^{\pi/2}\mathbf F(x(u,v),y(u,v),z(u,v))\cdot\mathbf n\,\mathrm dS

=\displaystyle-49\int_0^{\pi/2}\int_0^{\pi/2}(7\cos u\sin v\,\mathbf i-7\cos v\,\mathbf j+7\sin u\sin v\,\mathbf )\cdot\mathbf n\,\mathrm dS

=-343\displaystyle\int_0^{\pi/2}\int_0^{\pi/2}\cos^2u\sin^3v\,\mathrm du\,\mathrm dv=\boxed{-\frac{343\pi}6}

4 0
3 years ago
Three cups of baking soda are poured into 9 mixing bowls so that each bowl holds the same amount of baking soda.
Liono4ka [1.6K]

Answer: Each bowl gets 1/3 of a cup.

Step-by-step explanation:

3 cups divided into 9 bowls

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You can simplify this by dividing each side of the fraction by 3

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6 0
3 years ago
Ron's recycle shop had an old paper-shredding machine. Business was good, so he bought a new paper-shredding machine. The old ma
levacccp [35]

Answer: 1 hour 20 minutes

Step-by-step explanation:

Given : The old machine could shred a truckload of paper in 4 hours.

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The new machine could shred the same truckload in 2 hours.

Rate of work done by new machine = \dfrac{1}{2}

Let 't' be the time taken by both of them working together , then we have the following equation:-

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Since 1 hour = 60 minutes

Then, \dfrac{1}{3}\ \text{ hours}=\dfrac{1}{3}\times60=20\text{ minutes}

Hence, it will take 1 hour 20 minutes to shred the same truckload of paper if Ron runs both shredders at the same time.

8 0
3 years ago
What is the surface of a cylinder radius 8mm height of 20 mm
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Hey there :) You'll have to use the formula of cylinder to get your answer :
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pi = 22.7 or 22/7
r (radius of cylinder) = 8 mm
h = height of cylinder = 20mm

●Hence, just substitute your answer in the given formula and also don't forget to check whether the answer required needs to be in mm or cm.

Hope it helps :)
6 0
2 years ago
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