The best and most correct answer among the choices provided by the question is the fourth choice.

The best people for advising is <span>the government agency that regulates these types of chemicals.</span>
I hope my answer has come to your help. God bless and have a nice day ahead!

4 0

3 years ago

A circle has an initial radius of 50ft when the radius begins decreasing at a rate of 2ft/s. what is the rate of change of the a

valkas [14]

The area of the circle with radius r is
A = πr²

The rate of change of area with respect to time is
$\frac{dA}{dt} = \frac{dA}{dr} . \frac{dr}{dt} =2 \pi r. \frac{dr}{dt}$

The rate of change of the radius is given as
$\frac{dr}{dt} =-2 \, \frac{ft}{s}$
Therefore
$\frac{dA}{dt} =-4 \pi r \, \frac{ft^{2}}{s}$

When r = 10 ft, obtain
$\frac{dA}{dt}|_{r=10 \, ft} = -40 \pi \, \frac{ft^{2}}{s}$

Answer: - 40π ft²/s (or - 127.5 ft²/s)

7 0

3 years ago

A 4.0 Ω resistor has a current of 3.0 A in it for 5.0 min. How many electrons pass 3. through the resistor during this time inte

musickatia [10]

Answer:

Number of electrons, $n=5.62\times 10^{21}$

Explanation:

It is given that,

Resistance, R = 4 ohms

Current, I = 3 A

Time, t = 5 min = 300 s

We need to find the number of electrons pass through the resistor during this time interval. Let the number of electron is n.

i.e. q = n e ...............(1)

And current, $I=\dfrac{q}{t}$

$I\times t=n\times e$

$n=\dfrac{It}{e}$

e is the charge of an electron

$n=\dfrac{3\ A\times 300\ s}{1.6\times 10^{-19}}$

$n=5.62\times 10^{21}$

So, the number of electrons pass through the resistor is $5.62\times 10^{21}$ . Hence, this is the required solution.

6 0

3 years ago

What is the surface temperature of Sirius B in Kelvins?

Sauron [17]

Answer: The surface temperature of Sirius B is 25,200 Kelvins(K).

Explanation: You would think Sirius would have a surface temperature of 9,940 Fahrenheit. That is somewhat correct, but Sirius is a binary star consisting of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B. Sirius, Sirius A, and Sirius B, are all different stars. Sirius A has a temperature of 9,940 Kelvins, but Sirius B has a temperature of 25,200 Kelvins(K).

7 0

2 years ago

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