Physics, 14.10.2019 05:00 StephenCurry34

Raul wants to study how pot size affects the growth of plants. to do this, he intends to purchase three different pots of varying diameter. then, he will fill each pot with the same amount of soil and plant different kinds of flowers in each pot. finally, he will place the pots side by side in a sunny location and water each pot daily with the same amount of water. will raul's experimental set-up produce valid results?

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The answer position may vary. But the correct answer is D. No; Raul changes more than one variable so the results will be invalid.

Explanation:

Raul's experimental set-up will not produce valid results because he intends to change more than one variable.

One variable that Raul will change is the pot size. According to the description, however, Raul will also change one other variable—the type of flower that is planted. Even though Raul plans on using flowers only, he should use the same type of flower in each pot, not different types.

Valid results are only produced when only one variable is changed at a time.

Answer from: kennedy3076

No, Raul changes the more than one variable so the results will be invalid.

Answer from: Quest

the correct choice is a .

do not post any more test or exam questions on

Answer from: Quest

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

$x(t)=ax(x-6)$

where $a$ is unknown. because the position is parabolic, there is symmetry about the midpoint at $t=3$ , and we know that

$x(3)=10\implies -9a=10\implies a=-\dfrac{10}9$

so that the position function is

$x(t)=-\dfrac{10}9x(x-6)$

which means the velocity is

$v(t)=\dfrac{\mathrm dx}{\mathrm dt}=-\dfrac{20}9x+\dfrac{60}9$

then the total distance traveled is

$\displaystyle\int_{t=0}^{t=6}|v(t)|\,\mathrm dt=\left\{\int_{t-0}^{t=3}-\int_{t=3}^{t=6}\right\}v(t)\,\mathrm dt=20$

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at $x=0$ and ends at $x=0$ , so its displacement is 0.

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Raul wants to study how pot size affects the growth of plants. to do this, he intends to purchase th...