Answer:
(a). The decay constant is [tex]1.55\times10^{-5}\ s^{-1}[/tex]
The half life is 11.3 hr.
(b). The value of N₀ is [tex]2.38\times10^{11}\ nuclei[/tex]
(c). The sample's activity is 1.87 mCi.
Explanation:
Given that,
Activity [tex]R_{0}=10\ mCi[/tex]
Time [tex]t_{1}=4\ hours[/tex]
Activity R= 8 mCi
(a). We need to calculate the decay constant
Using formula of activity
[tex]R=R_{0}e^{-\lambda t}[/tex]
[tex]\lambda=\dfrac{1}{t}ln(\dfrac{R_{0}}{R})[/tex]
Put the value into the formula
[tex]\lambda=\dfrac{1}{4\times3600}ln(\dfrac{10}{8})[/tex]
[tex]\lambda=0.0000154\ s^{-1}[/tex]
[tex]\lambda=1.55\times10^{-5}\ s^{-1}[/tex]
We need to calculate the half life
Using formula of half life
[tex]T_{\dfrac{1}{2}}=\dfrac{ln(2)}{\lambda}[/tex]
Put the value into the formula
[tex]T_{\dfrac{1}{2}}=\dfrac{ln(2)}{1.55\times10^{-5}}[/tex]
[tex]T_{\dfrac{1}{2}}=44.719\times10^{3}\ s[/tex]
[tex]T_{\dfrac{1}{2}}=11.3\ hr[/tex]
(b). We need to calculate the value of N₀
Using formula of [tex]N_{0}[/tex]
[tex]N_{0}=\dfrac{3.70\times10^{6}}{\lambda}[/tex]
Put the value into the formula
[tex]N_{0}=\dfrac{3.70\times10^{6}}{1.55\times10^{-5}}[/tex]
[tex]N_{0}=2.38\times10^{11}\ nuclei[/tex]
(c). We need to calculate the sample's activity
Using formula of activity
[tex]R=R_{0}e^{-\lambda\times t}[/tex]
Put the value intyo the formula
[tex]R=10e^{-(1.55\times10^{-5}\times30\times3600)}[/tex]
[tex]R=1.87\ mCi[/tex]
Hence, (a). The decay constant is [tex]1.55\times10^{-5}\ s^{-1}[/tex]
The half life is 11.3 hr.
(b). The value of N₀ is [tex]2.38\times10^{11}\ nuclei[/tex]
(c). The sample's activity is 1.87 mCi.
Brainliest ASAP!!
Solve the equation 4(s+5)=60
Answer:
s=10
Explanation:
4(s+5)=60
4s+20=60
4s=40
s=10
In which box could “gas” be placed?
*C. W is not the answer
which one of the following is a derived Si unit a. Newton, b. Meter, c. Mole, d. Kiogram
Answer:
The SI is founded on seven SI base units for seven base quantities assumed to ... The SI derived units for these derived quantities are obtained from these ... mass density, kilogram per cubic meter, kg/m3 ... amount-of-substance concentration, mole per cubic meter, mol/m3 ... solid angle, steradian (a), sr (c), -, m2·m-2 = 1 (b).
Kilogram is a derived SI unit of the following.
Thus, A universal standard for expressing the magnitudes or quantities of significant natural events is the International System of Units.
The acronym SI, which derives from the French term Systèm international stands for the System of Units, also known as the metric system. The meter-kilogram-second (MKS) system, an earlier unit of measurement, serves as the foundation for the SI standard.
The SI standard is promoted and explained by the Bureau international des poids et mesures (BIPM). The organization was founded in 1875 and is known as the International Bureau of Weights and Measures in English. It is governed by the International Committee for Weights and Measures (CIPM).
Thus, Kilogram is a derived SI unit of the following.
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A car travels at a constant speed of 70 km/hr for 15 minutes. The car decreases its speed from 70 to 40 km/hr over the next two minutes and then continues to travel at a constant speed of 40 km/hr for the next 5 minutes Which of the following graphs best represents the car's motion during the given time period?
Answer:
A car travels at a constanT
please help
Which equipment is best to hold and to measure liquids?
A). flask and graduated cylinder
B). scale and ruler
C). caliper and thermometer
D). stopwatch and beaker
Answer:
I'm pretty sure that the answer is A
Which sentence describes Newton's first law?
A. Forces always come in pairs that have the same magnitude.
B. The action force applied by one object to another is opposite in
direction to the reaction force.
C. It takes a larger net force to accelerate an object at a greater rate.
D. Unbalanced forces cause an object to move.
SM
[tex]\Large{\red{\bf{\blue{\dag} Answer:-}}}[/tex]
Newton's First Law of Motion :
An object stays in rest or in uniform motion unless and until compelled by an external unbalanced force . This is also known as " Law of Inertia " .
Here this statement is best represented by the statement : Unbalanced forces cause an object to move. [ option c ]
More to know :-
Newton's 3 laws of motion :-
Newton's First Law of Motion :-
It states that an object stays in rest or in uniform motion unless and until compelled by an external unbalanced force . This is also known as " Law of Inertia " .
Ex - (i) We tend to fall backwards while standing in the bus , when it starts suddenly.
(ii) We tend to fall forward while standing in the bus , when it stops suddenly.
Newton's Second Law of Motion :-
It states that the rate of change of momentum is directly proportional to the applied force in the direction of the force . That is ∆p [tex]\propto[/tex] Force .
Ex - (i) When we push car & a truck with same force the car will have Greater acceleration due to less mass . (Imaginary case ).
(ii) We feel easy to push a empty cart than a full cart .
Newton's Third Law of Motion :-
It states that every action has equal and opposite reaction .
Ex - (i) We are able to walk on ground due to Newton's third law of motion .
(ii) When we push wall it also applies equal and opposite force .
"Unbalanced forces cause an object to move " is the sentence that describes Newton's first law.
Describe Newton's first law.A body remains in the state of rest or uniform motion in a straight line unless and until an external force acts on it.
The object is to be rest if the velocity and acceleration are zero. When an object is in motion, velocity is not equal to zero (v ≠ 0) but acceleration (a = 0) is equal to zero. Therefore, the object will continue in motion with constant velocity in the same direction.
Example:
If we jump from a bus while moving, our body will be like still moving in the same direction of the vehicle. When your feet hit the ground, the grounds act on your feet and stop moving. You will fall because the upper part of your body didn't stop and you will fall in the direction you were moving.
If the object have the greater mass, then the object will have more inertia. Forces can change the object's motion.
Hence, Option D is the correct answer.
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List two objects here on Earth that are sources of radiant energy. How can you tell they emit radiant energy?
What type of bond is shown in the figure?
Answer:
ionic
Explanation:
How does changing the number of neutrons affect an atom?
Answer:
If you change the number of neutrons in an atom, you get an isotope of the same element. The addition of a neutron can make an atom radioactive. When you change the number of protons in an atom, you will change the atom from one element to a different element.
Explanation:
The characteristics of the atomic nucleus allow to find the answer for the effect of the change of neutrons in an atoms is
The change in neutrons changes the atomic mass.
A chemical element is made up of protons, neutrons and electrons; the first two are in the atomic nucleus and the electrons are in orbits around them.
The number of protons corresponds to the atomic number and its change changes the type of element.
The neutrons that are neutral charge together with protons form the mass of the atom, as neutrons are neutral if the number does not affect the type of atom, but if its atomic mass changes.
Elements with the same atomic number, but different atomic mass, different number of neutrons are called isotopes; in general all elements have isotopes, for example hydrogen has an isotope called deuterium that has a neutral and another radioactive isotope called tritium that has two neutrons.
In conclusion using the characteristics of the atomic nucleus we find the answer for the effect of the change of neutrons in an atoms is
The change in neutrons changes the atomic mass.
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PLEASE HELP THIS IS DUE IN 10 MINUTES- (15 points!)
1st question- what are the weather fronts(use the pic for help)
2nd question- who has better weather— high pressure systems or low pressure systems and how do you know?
(Please add explanation)<3
Answer: I would say that B would have better weather because those dots on the right are cold fronts and the smooth side without the dots is a warm front. I hope this helps :)
Explanation:
Define what velocity means.
Answer:
The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g. 60 km/h to the north).
4. Hijackers are taking over a plane, They tell the pilot to get to Spain as fast as possible. The plane goes from 900
km/hr (beginning speed) to 1140 km/hr (final speed) in just 6 seconds. What is the acceleration of the plane?
Which of the following statements about the technique of hypnotic regression is not true?
O Recovered memories are not reliable.
Courts often depend upon recovered memories.
O Memories may be planted by the hypnotist.
The process may create stress for the subject.
Answer:
B. is the correct answer just took the topic review.
Explanation:
Edge2020. Hope that this helps! Peace and Love
Courts often depend upon recovered memories is the wrong statement about the hypnotic regression.
What is hypnotic regression?Hypnotic regression is a contentious method because it can have a number of negative effects on the subjects who undergo it. For the beginners, the memories recovered through any regression can be doubtful and not trust-worthy. All the suggestions or leading questions from the hypnotist or other people of witnesses can affect the memory.
The previous lives memories will be found by the hypnotic technique as a past life regression. If they used to remember the past life by this method they have high chance of getting into the traumas.
Regression therapy mostly used to identify the cause of your current thoughts and reactions. Therapists who is using this techniques to access subconscious memories that are guiding your current behaviour.
Regression therapy is a method of treatment that could approach and focuses on resolving particular past events that are thought to be interfering or relatable with a person's current mental and emotional well-being.
Hence, Option B is the correct answer.
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Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes. JoJo made 42 cupcakes What fraction of the cupcakes do Lucy and JoJo still need to make?
Answer:
9/20
Explanation:
According to this question, Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes while JoJo made 42 cupcakes. This means that in total, (42 + 35) cupcakes has been made by both Lucy and JoJo
That is, 77 cupcakes out of 140 has been made. This is 77/140 i.e. 11/20
Since 77/140 cupcakes has been made, Lucy and JoJo still need to make;
140 - 77 = 63 cupcakes to meet up their target for the school dance.
This means that the fraction left is 63/140
63/140 in its lowest term is 9/20
Hence, 9/20 of the cupcakes still need to be made by Lucy and JoJo.
Explanation: 140 - 35 = 105 - 42 = 63
yare yare daze
I use tusk act 4 main
If a racer maintained a constant speed, during which sections of the race would the racer's velocity be the same?
Sections 1 and 2
Sections 2 and 3
Sections 2 and 4
Sections 3 and 4
pls help!!
Answer:
Sections 3 and 4
Explanation:
The correct answer would be sections 3 and 4.
The velocity of an object is the speed of the object in a particular direction. In this case, the speed of the racer is constant irrespective of the distance or the direction. Hence, the sections of the race during which the racer's velocity would be the same would be the sections in which the racer faces the same direction - which is sections 3 and 4.
why are force and velocity different?
Answer: If you apply force to an object the velocity changes. But it doesn't work the other way around apply velocity and the force (no!) Velocity does not change on an object. A force pushes or pulls on an object, but velocity is simply something an object has I hope this makes sense to you. Hope this helps :)
Explanation:
What the meaning of centerpiece
Answer:
1 : an object occupying a central position especially : an adornment in the center of a table. 2 : one that is of central importance or interest in a larger whole the centerpiece of a political agenda.
Explanation:
Which information could a student determine from only the chemical formula of a protein
Answer:
the answer is (D) The number of atoms of each element in the protein
Explanation:
Answer:
Which information could a student determine from only the chemical formula of a protein
Which information could a student determine from only the chemical formula of a protein
Which information could a student determine from only the chemical formula of a protein
Explanation:
Which information could a student determine from only the chemical formula of a protein
Which information could a student determine from only the chemical formula of a protein
Which information could a student determine from only the chemical formula of a protein
If a train goes at constant speed of 40 miles per hour for one hour, then at constant
speed of 55 miles per hour for two hours, what is its average speed at the train?
Answer: because the train goes 72 mph for 2 hours
Explanation:
does the train go 72mph for 2 hours as well? if so the answer would be 324 because you have to add 90 twice scene it goes at that speed for 2 hours thats 180. assuming the train goes 72 mph for 2 hours it would be 144. then add 180 and 144 and you get 324 merry christmas and a happy newyear to you and your family
Which scenario does not describe an example of acceleration?
A car increases its speed while turning to the left.
A car decreases its speed while driving straight ahead.
A car maintains a constant speed while turning to the right.
A car maintains a constant speed while driving straight ahead.
Answer:
B is the right answer
Explanation:
It is decreasing.
A car maintains a constant speed while driving straight ahead.
What is acceleration?The acceleration of an object is the rate of change of velocity with time. It is measured in meter per second square.
Velocity of the carThe car undergoes velocity when there is change in direction of the speed.
Thus, the only option that does not describe acceleration is a car maintains a constant speed while driving straight ahead.
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Look at pic.... 2 examples of radiation and how they are radiation
Answer:21
Explanation:
If an object is moving with constant acceleration, its velocity must
a
change by varying amounts depending on its speed.
b
always decrease.
c
be constant also.
d
change by the same amount each second.
why is a 5 rupees coin attracted by a magnet? name the metal present in the coin
Hey Mate
See a coin is attracted bcoz he it has a metal names iron Which is easily attracted by the magnets
Hope, you fell my answer Helpful ( ◜‿◝ )♡
is isopropyl alcohol a element compound or mixture
Answer:
Isopropyl is an element compound.
Explanation:
An object with a charge of 1.2 C is located 4.5 m away from a second object that has a charge of 0.36 C. Find the electrical force that the objects exert on each other. Use 8.988×10 N⋅m2/C2 for the value of Coulomb's constant. Give your answer to two decimal places.
Answer:
[tex]1.917*10^8\ N[/tex]
Explanation:
Coulomb's law states that the electric force between two charges is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them. It is given by the formula:
[tex]F=k\frac{q_1q_2}{r^2}\\ \\q_1=first\ charge = 1.2C,q_2=second\ charge=0.36C,k=coulomb\ constant=8.988*10^9 N.m^2/C^2, r=distance=4.5m,F=force\\\\F=8.988*10^9*\frac{1.2*0.36}{4.5^2} =1.917*10^8\ N[/tex]
Which of the following are examples of acceleration?
A. A car speeds up after getting on a highway.
B. A car travels at a constant velocity on a highway.
C. A car slows down to exit a highway.
D. A car rounds a sharp curve on an off ramp at a constant speed.
Answer:
A, B, and D.
Explanation:
I've answered this exact question on a quiz. Hope it's not too late!
Answer:
A
C
D
Is the right answers not A.B,D.
trust
what should you do if the exercise schedule you make for yourself is not working out well by midweek
Answer:
I will find a solution.
Explanation:
i will figure out the problem,then solve it
Determine the average speed of an object that travels 200 miles in 4 hours.
Answer:
The average speed is 50 miles per hour
Explanation:
Speed is equals to distance divided by time
Then substitute your variables into the equation
Hope this helps
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how is kinetic energy is stored
Answer:
Explanation:
Kinetic energy can be stored. For example, it takes work to lift a weight and place it on a shelf or to compress a spring. ... Kinetic energy can also be transferred from one body to another in a collision, which can be elastic or inelastic. One example of an elastic collision would be one billiard ball striking another.
Explanation:
Kinetic energy can be stored. For example, it takes work to lift a weight and place it on a shelf or to compress a spring. ... Kinetic energy can also be transferred from one body to another in a collision, which can be elastic or inelastic. One example of an elastic collision would be one billiard ball striking another.
When performing a standard push-up, our hands should be placed on the ground... as close together as possible to make it the most challenging as close together as possible to make it the most challenging really wide to focus on chest development really wide to focus on chest development just outside our shoulders
Answer:
Kindly check the explanation section.
Explanation:
The statement given in the question or problem above is true or let's say it is correct. And the statement describes different kinds or types of push up.
Push up is a kind of excercise that is being done mainly to strengthen the arm and the cheat. The way one goes about it determines which part of the body one is strengthening.
The kind of push up in which one has to close up the gap between his or hands is known as the close push ups. This kind of push up strengthens the arm more than the other part of the body and the more one puts his or her hands closer the more problematic the push up excercise becomes.
Other types or kinds of push ups are the Slow Eccentric Push Ups, Wide Push Ups, Staggered Push Ups, T push ups, Fingertip Push Ups and many more.