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2 years ago

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A 12.0-g sample of carbon from living matter decays at the rate of 162.5 decays/minute due to the radioactive 14C in it. What wi

ll be the decay rate of this sample in 1000 years? What will be the decay rate of this sample in 50000 years?

1 answer:

Ghella [55]2 years ago

4 0

Answer:

a)143.8 decays/minute

b)0.41 decays/minute

Explanation:

From;

0.693/t1/2 = 2.303/t log (Ao/A)

Where;

t1/2=half-life of C-14= 5670 years

t= time taken to decay

Ao= activity of a living sample

A= activity of the sample under study

a)

0.693/5670 = 2.303/1000 log(162.5/A)

1.22×10^-4 = 2.303×10^-3 log(162.5/A)

1.22×10^-4/2.303×10^-3 = log(162.5/A)

0.53 × 10^-1 = log(162.5/A)

5.3 × 10^-2 = log(162.5/A)

162.5/A = Antilog (5.3 × 10^-2 )

A= 162.5/1.13

A= 143.8 decays/minute

b)

0.693/5670 = 2.303/50000 log(162.5/A)

1.22×10^-4 = 4.61×10^-5 log(162.5/A)

1.22×10^-4/4.61×10^-5 = log(162.5/A)

0.26 × 10^1 = log(162.5/A)

2.6= log(162.5/A)

162.5/A = Antilog (2.6 )

A= 162.5/398.1

A= 0.41 decays/minute

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Answer:

The cycle that moves carbon from one part of the Earth to another is called the carbon cycle.

Explanation:

The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Since our planet and its atmosphere form a closed environment, the amount of carbon in this system does not change. Where the carbon is located — in the atmosphere or on Earth — is constantly in flux.

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3 years ago

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During a testing process, a worker in a factory mounts a bicycle wheel on a stationary stand and applies a tangential resistive

olganol [36]

Answer:

The force is $F_c = 789.03 \ N$

Explanation:

From the question we are told that

The tangential resistive force is $F_t = 115 \ N$

The mass of the wheel is m = 1.80 kg

The diameter of the wheel is $d = 50.0 cm = 0.5 \ m$

The diameter of the sprocket is $d_c = 8.50 \ cm =0.085 \ m$

The angular acceleration considered is $\alpha = 4.30\ rad/s^2$

Generally the radius of the wheel is

$r = \frac{d}{2}$

=> $r = \frac{0.5}{2}$

=> $r = 0.25 \ m$

Generally the radius of the sprocket is

$r_c = \frac{d_c}{2}$

=> $r_c = \frac{0.085}{2}$

=> $r_c = 0.0425 \ m$

Generally the moment of inertia of the wheel is mathematically represented as

$I = m * r^2$

=> $I = 1.80 * 0.25^2$

=> $I = 1.1125 \ kg \cdot m^2$

Generally the torque experienced by the wheel due to the forces acting on it is mathematically represented as

$\tau = F_c * r_c - F_t * r$

Here $F_c$ is the force acting on the sprocket

So

$\tau = F_c * 0.0425 - 115 * 0.25$

$\tau = 0.0425F_c - 28.75$

Generally the torques that will cause the wheel to move with $\alpha = 4.30\ rad/s^2$ is mathematically represented as

$\tau = I * \alpha$

So

$0.0425F_c - 28.75 = I * \alpha$

$0.0425F_c - 28.75 = 1.1125 *4.30$

$0.0425F_c - 28.75 = 1.1125 *4.30$

$F_c = 789.03 \ N$

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3 years ago

the pitch that the average human can hear has a frequency of 20.0. If sound with this frequency travels through air with the spe

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There are problems with the first sentence, and it's not really needed when
working with this question. So let's just take the 20 (Hz ?) frequency from
the first sentence, and ignore the rest of it for right now.

Wavelength = (speed) / (frequency) =

(331 m/s) / (20 Hz) = <em>16.55 meters</em>.

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2 years ago

A ball is thrown vertically upward with a speed of 19.0 m/s. (a) How high does it rise? m (b) How long does it take to reach its

Arte-miy333 [17]

Answer with Explanation:

We are given that

Initial speed= $u=19 m/s$

a. $g=9.8m/s^2$

Final velocity of ball= $v=0$

$v=u-gt$

g is negative because the ball is going against to gravity.

$0=19-9.8t$

$9.8t=19$

$t=\frac{19}{9.8}=1.94 s$

$s=ut-\frac{1}{2}gt^2$

Using the formula

$s=19(1.94)-\frac{1}{2}(9.8)(1.94)^2$

$s=18.4 m$

a.The ball rise upto height 18.4 m

b.It take 1.94 s to reach its highest point.

c.Initial velocity=0,s=18.4 m

$s=ut+\frac{1}{2}gt^2$

$18.4=0(t)+\frac{1}{2}(9.8)t^2$

$18.4=4.9t^2$

$t^2=\frac{18.4}{4.9}$

$t=\sqrt{\frac{18.4}{4.9}}$

$t=1.94 s$

$v=u+gt$

Using the formula

$v=0+9.8(1.94)=19 m/s$

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3 years ago

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Help meeeeeeeeeeeeee! please show work! In a collision, Kara Less who was traveling at 11 m/s while texting in her 1300 kg car,

raketka [301]

The impulse experienced is -18,000 kg m/s

Explanation:

The impulse exerted on an object is equal to the change in momentum of the object. Mathematically:

$I=\Delta p = m(v-u)$

where

m is the mass of the object

v is the final velocity of the object

u is the initial velocity

$\Delta p$ is the change in momentum

I is the impulse

In the collision in this problem,

m = 1300 kg is the mass of the car

u = 11 m/s is the initial velocity

v = -2.5 m/s is the final velocity (negative, since it is in the opposite direction)

Substituting, we find

$I=(1300)(-2.5-11)=-17,550 kg m/s$

So the closest choice is

-18,000 kg m/s

Learn more about impulse and change in momentum:

brainly.com/question/9484203

#LearnwithBrainly

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3 years ago