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3 years ago

Help PLZ!!!! The ability of something to potentially catch on fire is ___________.

Physics

1 answer:

77julia77 [94]3 years ago

7 0

Answer:

Chemical Property

Explanation:

Examples of chemical properties include flammability, toxicity, acidity, reactivity (many types), and heat of combustion.

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The universe is mostly made up of what?

Viktor [21]

D. Empty Space

Imagine an apple in the center of a football field. Pretend like that apple is the nucleus of an atom. The electrons would be at the end-zones. The universe is just a butttonne of empty space

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4 years ago

You were in a tog-o-war contest which your team won. Write a letter to your friend that tells why your team won the contest. Rem

ollegr [7]

Answer:

Imagine a tug-of-war between you and one

friend. If you are stronger, you apply more

force to the rope. You pull your friend across

the line, and you are the winner! If your friend

is stronger, he might pull you across the line.

Sometimes the forces are equal. Neither you

nor your friend moves across the line. The two

forces are balanced.

We say that the net force on an object is the combination of all the forces acting on it. To find the net force of

forces that are acting in the same direction, add them together. For example, if you pull on a box with a force of 25

newtons (N) while your friend pushes the box (in the same direction you are pulling) with a force of 30 N, the net

force applied to the box in that direction is 55 newtons.

To find the net force of forces that are acting in opposite directions, subtract the smaller force from the larger

one. If you are pulling on a tug-of-war rope with a force of 40 N, and your friend is pulling with a force of 35 N in

the opposite direction, the net force on the rope is 5 newtons in your direction. You win!

Explanation:

3 0

3 years ago

a man can row a boat at 4 km per hour in still water. he rolls the boat two kilometre upstream and 2 kilometre back to a startin

stiv31 [10]

Answer:

I would say since it is still water the stream flow is 0km/h. Especially because he needs the same time upstream as He does down stream.

5 0

3 years ago

Read 2 more answers

Insert

nordsb [41]

A) 320 count/min

B) 40 count/min

C) 80 count/min, 11400 years

Explanation:

The activity of a radioactive sample is the number of decays per second in the sample.

The activity of a sample is therefore directly proportional to the number of nuclei in the sample:

$A\propto N$

where A is the activity and N the number of nuclei.

As a consequence, since the number of nuclei is proportional to the mass of the sample, the activity is also directly proportional to the mass of the sample:

$A\propto m$

where m is the mass of the sample.

In this problem:

- When the mass is $m_1 = 1 g$ , the activity is $A_1=16 count/min$

- When the mass is $m_2=20 g$ , the activity is $A_2$

So we can find A2 by using the rule of three:

$\frac{A_1}{m_1}=\frac{A_2}{m_2}\\A_2=A_1 \frac{m_2}{m_1}=(16)\frac{20}{1}=320 count/min$

The equation describing the activity of a radioactive sample as a function of time is:

$A(t)= A_0 e^{-\lambda t}$ (1)

where

$A_0$ is the initial activity at time t = 0

t is the time

$\lambda$ is the decay constant, which gives the probability of decay

The decay constant can be found using the equation

$\lambda = \frac{ln2}{t_{1/2}}$

where $t_{1/2}$ is the half-life, which is the amount of time it takes for the radioactive sample to halve its activity.

In this problem, carbon-14 has half-life of

$t_{1/2}=5700 y$

So its decay constant is

$\lambda=\frac{ln2}{5700}=1.22\cdot 10^{-4} y^{-1}$

We also know that the tree died

t = 17,100 years ago

and that the initial activity was

$A_0 = 320 count/min$ (value calculated in part A, corresponding to a mass of 20 g)

So, substituting into eq(1), we find the new activity:

$A(17,100) = (320)e^{-(1.22\cdot 10^{-4})(17,100)}=40 count/min$

We know that a sample of living wood has an activity of

$A=16 count/min$ per 1 g of mass.

Here we have 5 g of mass, therefore the activity of the sample when it was living was:

$A_0 = A\cdot 5 = (16)(5)=80 count/min$

Moreover, here we have a sample of 5 g, with current activity of $A=20 count/min$ : it means that its activity per gram of mass is

$A'=\frac{20}{5}=4 count/min$

We know that the activity halves after every half-life: Here the activity has became 1/4 of the original value, this means that 2 half-lives have passed, because:

- After 1 half-life, the activity drops from 16 count/min to 8 count/min

- After 2 half-lives, the activity dropd to 4 count/min

So the age of the wood is equal to 2 half-lives, which is:

$t=2t_{1/2}=2(5700)=11,400 y$

3 0

4 years ago

If any state tribunal decides a federal question and the litigant has no further remedy within the state court system, from whic

ANEK [815]

Answer: B. A hearing by a federal court of appeals

6 0

3 years ago