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2 years ago

What investigations allow for the control of variables

Physics

2 answers:

lina2011 [118]2 years ago

7 0

Most as long the hypothesis is a good answer and can be answered

PolarNik [594]2 years ago

3 0

I believe that the statement is true. Investigations allow for the control of variables. Changing variables will lead you to observations that may prove your hypothesis

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How can electric shock be prevented?

Nina [5.8K]

Wearing rubber or stay away from water or/ and a conductor

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2 years ago

A straight line is drawn on the surface of a 14-cm-radius turntable from the center to the perimeter. A bug crawls along this li

sleet_krkn [62]

Answer:

v = $\left[\begin{array}{c}0.66&0\end{array}\right]$ m/s

Explanation:

The position vector r of the bug with linear velocity v and angular velocity ω in the laboratory frame is given by:

$\overrightarrow{r}=vtcos(\omega t)\hat{x}+vtsin(\omega t)\hat{y}$

The velocity vector v is the first derivative of the position vector r with respect to time:

$\overrightarrow{v}=[vcos(\omega t)-\omega vtsin(\omega t)]\hat{x}+[vsin(\omega t)+\omega vtcos(\omega t)]\hat{y}$

The given values are:

$t=\frac{x}{v}=\frac{14}{3.8}=3.7 s$

$\omega=\frac{45\times2\pi}{60s}=4.7\frac{1}{s}$

8 0

2 years ago

An a.c. supply is connected to a wire stretched between the poles of a magnet. Which way does the wire move?

snow_lady [41]

The wire vibrates back and forth between the poles of the magnet.
The frequency of the vibration is the frequency of the AC supply.

7 0

1 year ago

What is the part of the earth that you walk on called?

olasank [31]

The part of the Earth that you walk on is called the CRUST.

6 0

2 years ago

A 75 kV x-ray machine gives an exposure of 200 mR for a 0.2-sec chest x-ray exam.

pashok25 [27]

Explanation:

Given that,

Potential = 75 kV

Exposure = 200 mR

Time = 0.2 sec

We need to calculate the x-ray fluence during this chest x-ray exam

Using formula of fluence

$x-ray\ fluence=exposure\times time$

Put the value into the formula

$x-ray\ fluence=200\times0.2$

$x-ray\ fluence=40\ mRs$

We need to calculate the energy fluence

Using formula of energy fluence

$E_{f}=40\times10^{-3}\times75\times10^{3}$

$E_{f} = 3000\ J$

We need to calculate dose -equivalent delivered to the bone, muscle, and fat

Using formula of dose

$D=\dfrac{E}{t}$

Where, D = dose

E = energy

t = time

Put the value into the formula

$D=\dfrac{3000}{0.2}$

$D=15.0\ kJ$

Hence, This is the required solution.

7 0

2 years ago