Determine the activity of the sample of cerium when the sample was 20 seconds old
Answers
Answer:
There are [tex]3.779\times 10^{23}[/tex] atoms when the sample of cerium is 20 seconds old.
Explanation:
The decay of isotopes is modelled after the following exponential expression:
[tex]N(t) = N_{o}\cdot e^{-\left(\frac{\ln 2}{t_{1/2}}\right)\cdot t }[/tex] (1)
Where:
[tex]N_{o}[/tex] - Initial number of atoms, dimensionless.
[tex]N(t)[/tex] - Current number of atoms, dimensionless.
[tex]t[/tex] - Time, measured in seconds.
[tex]t_{1/2}[/tex] - Half-time, measured in seconds.
Now we clear the half-time within (1):
[tex]\ln \frac{N(t)}{N_{o}} = -\frac{t\cdot \ln 2}{t_{1/2}}[/tex]
[tex]t_{1/2} = -\frac{t\cdot \ln 2}{\ln \frac{N(t)}{N_{o}} }[/tex]
If we know that [tex]N_{o} = 5\times 10^{23}[/tex], [tex]N(t) = 2\times 10^{23}[/tex] and [tex]t = 66\,s[/tex], then the half-life of the isotope is:
[tex]t_{1/2}=-\frac{(66\,s)\cdot \ln 2}{\ln \frac{2}{5} }[/tex]
[tex]t_{1/2}\approx 49.927\,s[/tex]
And the decay equation for the sample is described by:
[tex]N(t) = (5\times 10^{23})\cdot e^{-0.014\cdot t}[/tex]
Lastly, if we get that [tex]t = 20\,s[/tex], then the activity of the sample of cerium is:
[tex]N(20) = (5\times 10^{23})\cdot e^{(-0.014)\cdot (20)}[/tex]
[tex]N (20) \approx 3.779\times 10^{23}[/tex]
There are [tex]3.779\times 10^{23}[/tex] atoms when the sample of cerium is 20 seconds old.
Related Questions
Two cars, initially 12 meters apart, zip towards one another at the speeds shown. At what point will the collision occur? Explain how you arrived at your answer. Car A: 1.4m/s car B: 2.2m/s
Answers
Answer:
s₁ = 4.67 m from car A
Explanation:
Since, the cars are moving at a constant speed. Hence, we will apply the equation for uniform motion here:
s = vt
where,
s = distance covered
v = velocity
t = time taken
For Car A:
s₁ = (1.4 m/s)t
For Car B:
s₂ = (2.2 m/s)t
Because the time will be same at the collision. At collision the distance covered by Car A and Car B must be 12 m altogether. Hence:
s₁ + s₂ = 12 m
using values:
(1.4 m/s)t + (2.2 m/s)t = 12 m
t = 12 m/3.6 m/s
t = 3.333 s
Substitute this in the equation of s₁:
s₁ = (1.4 m/s)(3.33 s)
s₁ = 4.67 m from car A
please help!!!!
What are the mass and weight of a 50 kg stone on planet Earth?
Answers
Answer:
500 Newtons
Explanation:
Mass of the stone = 50 kg
Acceleration caused due to gravity on Earth (g) = 9.81 m/s^2 = 10 m/s^2
We know that,
F=ma
Hence,
W=mg
So,
The weight of the stone on Earth = 50 * 10 = 500 Newtons
A plane travels down a runway 2750 m before it lifts off at an angle of 37 degrees from the horizontal. The plane has traveled 1.8 km since its wheels left the ground. What is the displacement of the plane?
Answers
Answer: 4.236km
Explanation:
Let's define the point (x, y) as:
x = horizontal distance moved.
y = vertical distance moved.
If the plane starts in the point (0, 0) then:
"A plane travels down a runway 2750 m before it lifts off..."
At this time, the position will be:
P = (0 + 2750m, 0) = (2750m, 0).
"it lifts off at an angle of 37 degrees from the horizontal. The plane has traveled 1.8 km since its wheels left the ground."
In this case, as the angle is measured from the horizontal, the components will be:
x = 1.8km*cos(37°) = 1.438km
y = 1.8km*sin(37°) = 1.083 km
Then the new position is:
P = (2750m + 1.438 km, 0 + 1.083 km)
Let's write it using the same units for all the quantities:
we know that
1km = 1000m
Then:
2750m = (2750/1000) km = 2.750 km.
Then we can write the new position as:
P = (2.750 km + 1.438km, 1.083km) = (4.188km, 1.083km)
Now, we define the displacement as the distance between the final position and the initial position.
The distance between two points (a, b) and (c, d) is:
D = √( (a c)^2 + (b - d)^2)
In this case the points are:
(0, 0) for the initial position
(4.188km, 1.083km) for the final position.
And the displacement will be:
D = √( (4.188km - 0)^2 + (1.083 - 0)^2) = 4.236km
describe how you would see the apple in the dark.
Answers
How far(in meters) will you travel in 3 minutes running at a rate of 6 m/s
Answers
Answer:
1080 meters is the answer
To get this answer you multiply your speed by time which will give you the distance.
which is the larger value 5 * 10^5 or 3* 10^7
Answers
Explanation:
5x 10^5= 500,000
3x 10^7= 30,000,000
so the second one
Which image below is the best example of an exothermic reaction?
Answers
Answer:
ion
know man sorry
Explanation:
You drop a lead fishing weight and a filled water balloon. Which do you expect to fall faster?
Answers
I believe they should fall at the same pace.
Hallar la fuerza eletrica ejercida entre 2 cargas iguales de magnitud 1c separado en el aire una distancia de 1km Cual es el resultado? 1. (2,3*10^-8new) 2. (8,1*10^-6new) 3. (3,2*10^-8new)
Answers
Answer:
La fuerza eléctrica ejercida entre 2 cargas iguales de magnitud 1 C separado en el aire una distancia de 1 km es 9,000 N.
Explanation:
La ley de Coulomb se utiliza para calcular la fuerza eléctrica que actúa entre dos cargas en reposo. Es decir, esta ley permite predecir la fuerza electrostática de atracción o repulsión existente entre dos partículas según su carga eléctrica y la distancia entre ellas.
La fuerza eléctrica con la que dos cargas puntuales son atraídas o repelidas en reposo es directamente proporcional a su producto e inversamente proporcional al cuadrado de la distancia que las separa, expresada como:
[tex]F=k*\frac{q1*q2}{d^{2} }[/tex]
donde:
F es la fuerza eléctrica de atracción o repulsión. En el S.I. se mide en Newtons (N). q1 y q2 son lo valores de las dos cargas puntuales. En el S.I. se miden en Culombios (C). d es el valor de la distancia que las separa. En el S.I. se mide en metros (m). k es una constante de proporcionalidad llamada constante de la ley de Coulomb. Depende del medio en el que se encuentren las cargas. En concreto para el vacío k es aproximadamente 9*10⁹ N·m²/C² utilizando unidades en el S.I.En este caso:
q1= 1 Cq2= 1 Cd= 1 km= 1,000 mReemplazando:
[tex]F=9*10^{9} \frac{N*m^{2} }{C^{2} } *\frac{1 C* 1 C}{(1,000 m)^{2} }[/tex]
Resolviendo obtenes:
F= 9,000 N
La fuerza eléctrica ejercida entre 2 cargas iguales de magnitud 1 C separado en el aire una distancia de 1 km es 9,000 N.
PLEASE HELP!! ILL MARK BRAINLYEST!!
New substances are produced in a chemical change.
True
False
Answers
Whats the cell that’s based on that persons sex
Answers
Answer:
gamete i think
6. What is fuel needed for in space?
7. Could a rocket traveling at a speed of
10,000 km/h get into space? Explain.
8. Why is thrust also known as the
reaction force?
9. Why does a rocket not need to burn
fuel to keep moving once it is in space?
Answers
6. fuel is needed in space to power certain things like engines.
7. It couldn't, as the lowest speed acceptable to get into space is 7.9 km per second (28,440 km per hour). This is because to break into the barrier that no longer contains oxygen, you would need to be going at an extremely fast rate.
8. It involves Newton's 3rd law. The movement requires that same thrust to be thrown back, also.
9. There is no gravity. So, basically, you just float.
which substance can be separated by physical means and it is not the same throughout.
A.a compound
B.a heterogeneous mixture
C.an element
D.a homogeneous solution
Answers
Answer:
B. heterogenous mixture
Explanation:
The substance that can be separated by physical means include heterogenous mixtures, where the components forms separate faces. They can be easily separated using methods based on their physical properties.
What is heterogenous mixtures?Mixtures are combination of two or more individual components mixed physically or through chemical bonds. There are both homogenous and heterogenous mixtures.
In homogenous mixtures all the components are forms a single phase and appear to be one system. For example, salt solution, sugar solution etc. are homogenous mixtures.
In heterogenous mixtures, the components forms different phases which appears to be separated components. They are just physically mixture components and can be easily separated using physical methods.
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The equation F = M x a represents
A. Newton’s third law
B. Newton’s first law
C. Newton’s second law
Answers
Answer:
it C
Explanation:
and have a good day :)))
Answer : (c) Newton's second law
The formula (F = m x a) comes under Newton's second law of motion, which revolves around the concept of momentum and force.
The Federalists and Anti-Federalists argued primarily over which issue?
Answers
A 20 kg fish swimming at 2 m/s swallows a 5 kg fish at rest. What is the speed of the large fish after lunch
Answers
Answer:
1.6m/s
Explanation:
Given parameters:
Mass of the big fish = 20kg
Mass of small fish = 5kg
Speed of big fish = 2m/s
Speed of small fish = 0m/s
Unknown:
Speed of the large fish after lunch = ?
Solution:
The momentum of the big fish before and after feeding is conserved.
Initial momentum = Final momentum
m₁v₁ + m₂v₂ = v (m₁ + m₂)
m₁ is mass of the big fish
v₁ is the speed of the big fish
m₂ is mass of the small fish
v₂ is the speed of the big fish
v is the final speed
Now insert the parameters and solve;
20 x 2 + 5(0) = v(20 + 5)
40 = 25v
v = [tex]\frac{40}{25}[/tex] = 1.6m/s
1 pts
Question 13
Which statement best describes the consequences of a plant's leaf cells suddenly losing their
chloroplasts?
The leaf cells would divide rapidly.
The leaf cells would evolve into animal cells.
The leaf cells wouldaccumulate too much food and convert it to starch.
The leaf cells would be unable to convert the sun's energy to make food.
Question 14
1 pts
Answers
Answer:
The leaf cells would be unable to convert the sun's energy to make food.
Explanation:
The chloroplast in the leaf are used to make food for the plant. If the leaf loses its chloroplast, the leaf with not be able to use solar energy to manufacture their food.
During photosynthesis, green plants manufacture their food. They use sunlight to cause a reaction between carbon dioxide and water. The sunlight is trapped using chlorophyll present in the leaf. In the absence of the chlorophyll contained in the chloroplast, no solar energy would be generated to cause the reaction to take place.you are flying on an airplane and you overhear two pasengers comment that flight attendants must be very skiled, one says "when the flight attendants pour coffee they must take into account the forward motion of the airplane and pour the coffee in frount of the cup so that it will land in the cup." The other passenger replies, "flight attendants must have to study the laws of motion as part of their training!" What would Isaac Newton say about this conversation? Ik that was long but ill make it worth a lot of points for your trouble.
Answers
How do you get out of a room with only a mirror and a table?
Look in the mirror you see what you saw, use the saw to cut the table, half and half makes a hole, jump in it.
Thought you would like that.
A bicycle gear wheel is a disc with 50 ‘teeth' equally spaced around its edge, as shown. The gear wheel is rotated 10 times each second. A springy strip of metal is vibrated by the rotating ‘teeth'. The metal strip produces a sound of frequency that is equal to the frequency of vibration of the strip
Answers
Answer:
0.66mExplanation:
The question is not complete, here is the complete question, also see attached the image.
"A bicycle gear wheel is a disc with 50 ‘teeth’ equally spaced around its edge, as shown. The gear wheel is rotated 10 times each second. A springy strip of metal is vibrated by the rotating ‘teeth’. The metal strip produces a sound of frequency that is equal to the frequency of vibration of the strip. The speed of sound in air is 330ms–1. What is the wavelength of the emitted sound?"
given data
number of teeth= 50
we are told that the gear is rotated 10 times in 1 sec,
hence the frequency of the rotation past the strip is
=50*10
=500Hz
speed of sound= 330m/s
we know that
[tex]v_w = f \Lambda[/tex]-----------1
where Vw is the speed of sound,
f is its frequency, and
λ is its wavelength.
λ=Vw/f
λ=330/500
λ=0.66m
A car runs for about 10 years during its average useful life. If the odometer reads 120,000 miles at the end, what was the average speed of the car in mph
Answers
Answer:
12000 mph
Explanation:
Given that,
Distance read by the odometer = 120,000 miles
Duration of car, t = 10 years
We need to find the average speed of the car. Speed of an object is equal to the total distance covered divided by total time taken. So,
[tex]v=\dfrac{120000}{10}\\\\=12000\ mph[/tex]
So, the average speed of the car is 12000 mph.
A 62Kg rock climber is attached to a rope that is allowing him to hang horizontally with his feet against the wall. The tension of the rope is 7.1x10^2 N, and the rope makes an angle of 32 degrees with the horizontal. Determine the force exerted by the wall on the climber's feet? I need some help with understanding the problem through a FBD as well as how I will find the x and y components. Thank You !
Answers
Answer:
R= 602 .11 N
Explanation:
The horizontal component of tension T will give reaction of the wall and the vertical component of T will balance the weight of of the climber .
T cos32 = R
710 x .848 = R
R= 602 .11 N .
Four forces are exerted on an object as shown below: A square is shown with an arrow pointing up labeled 3 N, an arrow pointing right labeled 2 N, an arrow pointing down labeled 4 N and an arrow pointing left labeled 2 N In which direction will the object move? Up Down Left Right
Answers
Answer:— A square labeled Object B is shown with an arrow pointing up labeled 3 N, an arrow pointing right labeled 2 N, an arrow pointing down labeled 3 N and an arrow pointing left labeled 1 N. In which direction will the objects move? Object A will move down and Object B will move up.
Explanation:
Answer:
The answer is down.
Explanation:
The forces on the left and right sides are balanced forces making the object not move in left or right directions. The force on the object is also shown to be 4N down and 3N up. The object will move toward the side with more force and that is down.
Can somebody help me with this carbon nuclides question please?
Answers
Answer:
isotopes
Explanation:
because all of them have the same proton number which is the atom of the same element
Ana vive a 3 km del instituto y María en la misma carretera, 500 m. Más lejos. Todas las mañanas, a las ocho y cuarto, cogen la bici para ir a clase. Ana pedalea a 6 m/s y María a 8 m/s. A) ¿Cuándo y dónde se encuentran? B) A que velocidad tendría que pedalear Ana como mínimo para que María no la alcanzase antes de llegar al instituto
Answers
Answer:
A) Ana y María e encuentran a las 8 hs 19 minutos 10 segundos (250 segundos después).
María y Ana se encuentran cuando aún faltan 1500 metros para llega al instituto.
B) Ana tendría que pedalear como mínimo para que María no la alcanzase antes de llegar al instituto a una velocidad de 6.857 [tex]\frac{m}{s}[/tex].
Explanation:
A) Un movimiento es rectilíneo cuando un objeto describe una trayectoria recta, y es uniforme cuando su velocidad es constante en el tiempo. En otras palabras, el Movimiento Rectilíneo Uniforme es una trayectoria recta, su velocidad es constante y su aceleración es nula.
Para una posición inicial x0 y una velocidad v que tiene el cuerpo a lo largo del movimiento, la posición para cualquier tiempo está dada por:
x(t)= x0 + v*t
Estableciendo el origen de referencia en el instituto, se tienen los siguientes valores:
x0ana= 3 km= 3000 mx0maria= 3500 mPor otro lado, Ana pedalea a 6 m/s y María a 8 m/s.
Entonces, como Ana y María se acercan al origen de referencia, la escuela, se la ecuación del movimiento para cada una de ellas es:
xana= 3000 - 6*txmaria= 3500 - 8*tAmbas se encuentra cuando la posición de ellas sea la misma, esto es xana=xmaria. Entonces:
3000 -6*t= 3500 - 8*t
Resolviendo:
-6*t + 8*t= 3500 - 3000
2*t= 500
t= 500÷2
t=250 s= 4 minutos 10 segundos
Ana y María se encuentran a las 8 hs 19 minutos 10 segundos (250 segundos después).
Para conocer la posición en la que se encuentran debes sustituir el tiempo en la ecuación del movimiento de alguna de ellas:
xana=3000 - 6*250
xana= 1500 m
Es decir, María y Ana se encuentran cuando aún faltan 1500 metros para llega al instituto.
B) Para que esto ocurra Ana y María deben llegar al instituto al mismo tiempo. Entonces, el tiempo que tarda María en llegar a al origen de referencia, la escuela, es:
0= 3500 - 8*t
Resolviendo:
3500=8*t
3500÷8= t
437.5 segundos= t
Así que, si Ana 437.5 segundos o menos, María no la alcanzaría. Siendo la velocidad la relación entre el espacio recorrido por un objeto y el tiempo empleado para ello, entonces la velocidad de Ana se calcula como:
[tex]velocidad=\frac{distancia}{tiempo}[/tex]
[tex]velocidad=\frac{3000 metros}{437.5 segundos}[/tex]
velocidad= 6.857 [tex]\frac{m}{s}[/tex]
Ana tendría que pedalear como mínimo para que María no la alcanzase antes de llegar al instituto a una velocidad de 6.857 [tex]\frac{m}{s}[/tex].
While traveling along a highway a driver slows from 34 m/s to 15 m/s in 12 seconds. What is the automobile’s acceleration? (Remember that a negative value indicates a slowing down or deceleration.
Answers
Answer:
a=-1.58 m/s^2
Explanation:
Vo=34m/s
Vf=15m/s
t=12s
a= dV/dt = (Vf-Vo) /t = (15-34)/12
= - 19/12 = - 1.58m/s2
When the cornea and lens of the eye do not properly focus
light onto the retina, corrective lenses are needed. When are concave lenses
appropriate for vision correction?
Answers
Answer:
When there is nearsightedness or myopia
Explanation:
As, in myopia the image is formed in front of the retina.
Which makes things looking at things near very easy, but looking at far away things very difficult.
So concave lens makes things look bigger, so therefore, it is used during myopia, to make things look bigger when they are far away
what is the weight of a 75 kg sack of flour on Earth
Answers
Sometimes people say it’s 10 instead of 9.8 so you can say it’s 750 N as well
We have that the weight of a 75 kg sack of flour on Earth is
[tex]W=735.75N[/tex]
From the Question we are told that
Mass =75kg
Generally
The Gravitational pull on earth is approximately
g=9.81
Generally the equation for Weight is mathematically given as
[tex]W=Mass * gravity[/tex]
[tex]W=735.75N[/tex]
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Which of the following is the equation for calculating daily caloric needs? A. BMR calories + Digestion calories B. BMR calories + Activity Level calories + Digestion calories C. BMI + Activity Level calories D. Activity Level calories + Digestion Calories
Answers
Explanation:
To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows: If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2. If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375.
HAPPY TO HELP
Energy is measured in form of calories.
What is energy?Energy is the ability or capability to do tasks, such as the ability to move an item (of a certain mass) by exerting force. Energy can exist in many different forms, including electrical, mechanical, chemical, thermal, or nuclear, and it can change its form.
To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:
If you are sedentary (little or no exercise) :
Calorie-Calculation = BMR x 1.2.
If you are lightly active (light exercise/sports 1-3 days/week) :
Calorie-Calculation = BMR x 1.375
Energy is measured in form of calories.
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A jet plane flies at a velocity of 200 m/s, east in still air. a) If it flies into a 20 m/s wind heading west, what is its velocity relative to the ground? b) If it flies into a 20 m/s wind heading east, what is its velocity relative to the ground?
Answers
Answer:
Explanation:
a) If it flies into a 20 m/s wind heading west
The wind blows against the velocity of plane
resultant velocity = 200 - 20 = 180 m /s
velocity relative to ground = 180 m /s
b ) If it flies into a 20 m/s wind heading east,
wind will support the velocity of plane
resultant velocity = 200 + 20 = 220 m /s .
velocity relative to ground = 220 m /s .
Answer:
so mas o menos
Explanation:
a) If it flies into a 20 m/s wind heading west
The wind blows against the velocity of plane
resultant velocity = 200 - 20 = 180 m /s
velocity relative to ground = 180 m /s
b ) If it flies into a 20 m/s wind heading east,
wind will support the velocity of plane
resultant velocity = 200 + 20 = 220 m /s .
velocity relative to ground = 220 m /s .
How much does the force increase if each mass is doubled?
Answers
Answer:
The force will also double
Explanation: