What is most often given a value of zero to describe an object position on a srtaight line

Stand next to a partner so that you are side-by-side. Each of you should hold your left arm out to the side and then point with

riadik2000 [5.3K]

Answer:

They would be pointing in the same direction

Explanation:

If they were facing each other then it may seem like they are pointing in different directions they would still point the same way.

5 0

2 years ago

The half-life of Iodine-131 is 8.0252 days. If 14.2 grams of I-131 is released in Japan and takes 31.8 days to travel across the

MakcuM [25]

Answer:

Explanation:

Half-life problems are modeled as exponential equations. The half-life formula is $P=P_o\left (\dfrac{1}{2} \right)^{\frac{t}{k}}$ where $P_o$ is the initial amount, $k$ is the length of the half-life, $t$ is the amount of time that has elapsed since the initial measurement was taken, and $P$ is the amount that remains at time $t$ .

$P=14.2\left (\dfrac{1}{2} \right)^{\frac{t}{8.0252}}$

<u>Deriving the half-life formula</u>

If one forgets the half-life formula, one can derive an equivalent equation by recalling the basic an exponential equation, $y=a b^{t}$ , where $t$ is still the amount of time, and $y$ is the amount remaining at time $t$ . The constants a and b can be solved for as follows:

Knowing that amount initially is 14.2g, we let this be time zero:

$y=a b^{t}$

$(14.2)=ab^{(0)}$

$14.2=a *1$

$14.2=a$

So, $a=14.2$ , which represents out initial amount of the substance, and our equation becomes: $y=14.2 b^{t}$

Knowing that the "half-life" is 8.0252 days (note that the unit here is "days", so times for all future uses of this equation must be in "days"), we know that the amount remaining after that time will be one-half of what we started with:

$\left(\frac{1}{2} *14.2 \right)=14.2 b^{(8.0252)}$

$\dfrac{7.1}{14.2}=\dfrac{14.2 b^{8.0252}}{14.2}$

$0.5=b^{8.0252}$

$\sqrt[8.0252]{\frac{1}{2}}=\sqrt[8.0252]{b^{8.0252}}$

$\sqrt[8.0252]{\frac{1}{2}}=b$

Recalling exponent properties, one could find that $\left ( \frac{1}{2} \right )^{\frac{1}{8.0252}}=b$ , which will give the equation identical to the half-life formula. However, recalling this trivia about exponent properties is not necessary to solve this problem. One can just evaluate the radical in a calculator:

$b=0.9172535661...$

Using this decimal approximation has advantages (don't have to remember the half-life formula & don't have to remember as many exponent properties), but one minor disadvantage (need to keep more decimal places to reduce rounding error).

So, our general equation derived from the basic exponential function is:

$y=14.2* (0.9172535661)^t$ or $y=14.2*(0.5)^{\frac{t}{8.0252}}$ where y represents the amount remaining at time t.

<u>Solving for the amount remaining</u>

With the equation set up, substitute the amount of time it takes to cross the Pacific to solve for the amount remaining:

$y=14.2* (0.9172535661)^{(31.8)}$ $y=14.2*(0.5)^{\frac{(31.8)}{8.0252}}$

$y=14.2* 0.0641450581$ $y=14.2*(0.5)^{3.962518068}$

$y=0.9108598257$ $y=14.2* 0.0641450581$

$y=0.9108598257$

Since both the initial amount of Iodine, and the amount of time were given to 3 significant figures, the amount remaining after 31.8days is 0.911g.

8 0

1 year ago

Which character trait below is a trait that both Michael Faraday and Nikola Tesla had?

-Dominant- [34]

They were both odd and obsessive

7 0

3 years ago

Cody is using a sling shot and rock to knock down a can that he has placed on a tree stump. His first attempt fails because he r

Archy [21]

it is believed to be the letter a

3 0

2 years ago

Read 2 more answers

Mr. Cohen is a scientist who is testing the efficiency of a 9 V battery by measuring how much electrical energy it releases. He

Mashcka [7]

Answer:

D. (7 ÷ 9) × 100

Explanation:

In order to solve this problem we need the answers of the problem, performing an internet search this problem is found, with the different answer options

A. (7 − 9) × 100

B. (9 − 7) × 100

C. (9 ÷ 7) × 100

D. (7 ÷ 9) × 100

Returning to the problem of the total energy of 9V only 7 volts were used. If we make a rule of three we realize that:

$100 = 9V\\x = 7\\x = \frac{7*100}{9} \\$

x = 77.77%

In this way we determine that the answer is D.

5 0

2 years ago