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.
Red blood cells need iron. They store iron and typically contain more iron than the fluid around them does. Which action would show the blood cells doing active transport?
A.pushing iron out
B.bringing iron in
C.swelling
D.shrinking
are eggs a element, a compound, or a mixture
Answer:
I'm gonna go with compund
Answer: a mixture because it is made out of some other substances.
Explanation:
в горизонтальном положении бревно длиной 18 м можно уравновесить на подставке, отстоящей на 3 м от его толстого конца. Если же подставка находится в 6 м от толстого конца, и на тонкий конец сядет рабочий массой 60 кг, то бревно снова будет в равновесии. Определите массу бревна.
Ответ:
90кг
Пояснение:
Найдите эскиз прилагаемой схемы. Масса бревна M размещается на отметке 3 см от толстого конца, а стержень размещается на отметке 6 см от массы бревна.
Согласно принципу момента, сумма момента по часовой стрелке равна сумме момента против часовой стрелки.
Вес корпуса в более тонкой части W = мг
W = 60 × 10 = 600 Н
Момент по часовой стрелке = 600 × 9
CW момент = 5400 Нм
Момент против часовой стрелки = M × 6
Момент ACW = 6M
Уравнять оба момента
6M = 5400
М = 5400/6
М = 900Н
Масса бревна = 900/10
Масса бревна = 90кг
What forces are included on a free-body diagram for a chosen object?
a.all the forces exerted on or by the object.
b.all the forces exerted by the object, but not on it
c. all the forces exerted on the object, but not by it
d. all forces that exist within the neighborhood of the object
Answer:
C
Explanation:
A free-body diagram shows all the forces exerted or applied on an object.
A free-body diagram includes all the forces exerted on or by the object. Hence, option A is correct.
What is a free-body diagram?A free-body diagram is a diagrammatic representation of a single body or a group of bodies that are separated from their surroundings and display all the forces acting on them. A free-body diagram (FBD; sometimes known as a force diagram) is a graphical representation used in physics and engineering to show the applied forces, moments, and consequent reactions on a body under a specific condition.
It shows a body or group of connected bodies along with all the applied forces, times, and reactions that the body experiences. The body could be compact or comprise several interior pieces (like a truss) (such as a beam). To answer difficult problems, a series of free bodies and other diagrams may be required.
Hence, all the forces exerted on or by the object are included in the free-body diagram.
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Which statement explains the similarity between momentum and kinetic energy of an object?
A. Both are inversely proportional to the mass and velocity of the object.
B. Both are directly proportional to the mass and velocity of the object.
C. Both are inversely proportional to force and displacement.
D. Momentum is directly proportional to the mass of the object and the square of the velocity of the object.
E. Kinetic energy is directly proportional to the mass of the object and the square of the velocity of the object.
Please help asap
Answer:
B. Both are directly proportional to the mass and velocity of the object.
Answer:
E. Kinetic energy is directly proportional to the mass of the object and the square of the velocity of the object.
Explanation:
I just took the test and it was right. Trust me on this one
What is the name of the kind of stretch that involves stretching as far as you can and then holding for 10-30 seconds
Question 2 options:
PNF
ballistic
dynamic
static
Answer:
Static stretching.
Explanation:
It is static stretching because it is a form of stretching which u can do actively for a period of time and you hold position for about 30 to 60 seconds which allow the muscles and connective tissues to lengthen. It is done after work out with out movement in order to loosen up muscles so as to gain flexibility.
can energy change in physical change
You row a boat perpendicular to the shore of a river that flows at 3 m/s. The velocity of your boat is 4 m/s relative to the water. What is the velocity of your boat relative to the shore?
Answer:
The velocity vBW of the boat relative to the water is 4.0 m/s, directed perpendicular to the current, as in Figure 3.18.
Explanation:
The boat is perpendicular to the shore. Then the net velocity of the boat with respect to river is 5 m/s. The observer feels like the boat is moving slower than they appear actually.
What is relative velocity ?Relative velocity is velocity of an object measured with respect to other object which can be of stationary or moving with a speed. Thus speed relative to another object is called the relative velocity.
The relative velocity is what's the speed for an observer but it differs from actual velocity. Sometimes it may slower or faster depending on the object with which a we are relating the speed.
Given that the speed of the boat = 4 m/s
speed of river = 3 m/s.
Both are perpendicular and the net velocity of the boat is :
r = √(3² + 4²) = 5 m/s.
Hence, the velocity of the boat relative to the shore will be 5 m/s.
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Warmer weather caused Galetown to have more severe storms.
Answer:
it will have to rise higher in the before the temperature of the air parcel and the surrounding air are equal. Which means the climate has rised
Explanation:
The climate rised
hope this helps!
HELLO! Please Help me.
I can't do it! it's Science
Answer:
9V
Explanation:
V=IR
V=2.5*3.6
V=9
Answer:
9V
Explanation:
V =IR
V =2.5 * 3.6
V = 9V
Can someone please Help me
Answer: The answer to 3 to is less inertia. The answer to 4 is large amount of inertia. The answer to 5 is large amount of inertia. The answer to 6 is more fuel. Number 6 is kind of unkown considering I can’t see the other answer but I guess it’s more fuel.
Explanation: Inertia is the resistance of the object to any change in its motion, including a change in direction. An object will stay still or keep moving at the same speed and in a straight line, unless it is acted upon by an external unbalanced force. So when there is more inertia, it’s harder to control, but when it has less inertia, it’s more loose and easier to move around.
Between 1990 and 2010, more than 8.6 million acres of forest were destroyed in Indonesia, Malaysia, and Papua New Guinea to build palm oil plantations. These forests are homes to orangutans, elephants, tigers, and other animals. How will this activity affect the forest ecosystem?
Answer:
1.More number of natural disasters will occur.
2. Disease will spread.
Explanation:
An ecosystem is a geographic area where plants, animals, and other organisms live in and interact with each other in an environment.
Forests are homes to orangutans, elephants, tigers, and other animals.
As more than 8.6 million acres of forest were destroyed in Indonesia, Malaysia, and Papua New Guinea to build palm oil plantations, this may lead to the following consequences:
1.More number of natural disasters will occur.
2. Disease will spread.
You are building a bridge, and you want to use a metal with the strongest metallic bonds. Which hypothetical element would you use? Metal A - melting point of 236 degrees Celsius Metal B - melting point of 2,678 degrees Celsius Metal C - melting point of 1,362 degrees Celsius Metal D - melting point of 800 degrees Celsius
Answer:
Metal B
Explanation:
Metallic bonds melt at high temperatures. Metal B has the highest melting point of the 4 metals given.
Problem #2: An apple is thrown upward with an initial velocity of +24.0 m/s. a. Sketch the apple's trip and label what you know. b. How high will the apple go? (Ans: +29.4 m) c. What is the total time needed for the apple to return to its original position? (Ans: 4.90 s)
Answer:
The answer is below
Explanation:
a) The initial velocity (u) = 24 m/s
We can solve this problem using the formula:
v² = u² - 2gh
where v = final velocity, g= acceleration due to gravity = 9.8 m/s², h = height.
At maximum height, the final velocity = 0 m/s
v² = u² - 2gh
0² = 24² - 2(9.8)h
2(9.8)h = 24²
2(9.8)h = 576
19.6h = 576
h = 29.4 m
b) The time taken to reach the maximum height is given as:
v = u - gt
0 = 24 - 9.8t
9.8t = 24
t = 2.45 s
The total time needed for the apple to return to its original position = 2t = 2 * 2.45 = 4.9 s
How far will a 600kg boat travel in 12 s if there is a constant 900N force on it and it starts from rest?
Answer:
d = 108 m
Explanation:
Given that,
Initial speed, u = 0
Mass of the boat, m = 600 kg
Time, t = 12 s
Force on boat, F = 900 N
Firstly, we can find the acceleration of the boat using formula, F = ma
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{900\ N}{600\ kg}\\\\a=1.5\ m/s^2[/tex]
Let it will travel d distance. Using second equation of motion to find it as follows :
[tex]d=ut+\dfrac{1}{2}at^2\\\\d=0+\dfrac{1}{2}\times 1.5\times (12)^2\\\\d=108\ m[/tex]
So, the boat will travel 108 m.
A cat sits on a high brance. what kind of energy does it possess? (APEX)
A. Kinetic
B. Chemical
C. Potential
D. Nuclear
Answer:
C. Potential Energy ...............
why can't you run from momentum ?
What will most likely occur if sulfur forms an ionic bond with another element?
A. Sulfur will accept electrons.
B. Sulfur will donate electrons
C. Sulfur will become a positive ion.
D. Sulfur will become less stable.
How can Newton's third law describe the forces affecting a rocket as it
descends to Earth's surface?
A. The rocket can move downward because the forces acting on it
are unbalanced.
B. The maximum amount of force the rocket engines can provide
determines how much mass the rocket can lift.
C. The rocket pushes through the air with a force equal to that of
Earth's gravity pulling on the rocket.
D. The force the rocket exerts on the air is in the direction opposite to
the force that the air exerts on the rocket.
Answer:
its D
Explanation:
i took the quiz
The force the rocket exerts on the air is in the direction opposite to
the force that the air exerts on the rocket.
What is force?A force is an effect that can alter an object's motion according to physics. An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.
Every action has an equal and opposite response, according to Newton's Third Law. Burning fuel in a rocket causes a push that propels the rocket forward from the front. As a result, the exhaust gas is pushed in the opposite direction and equally.
The force the rocket exerts on the air is in the direction opposite to
the force that the air exerts on the rocket.
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2. The dust usually sticks ton TV iscreen because dust
A. Falls on the TV screen
B.Particles are metallic conductors
C.Is attracted by magnets in the TV screen
D. Is attracted
by static charges on the TV scien.
Answer:c
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.
Mr. Mehta cut several 275-centimeter lengths of wallpaper to put in his
dining room. How many meters long was each piece of wallpaper?
Answer:
2.75 meters.
Explanation:
1 meter = 100 centimeters.
There are 275 centimeters.
275/100=2.75
So, each piece of wallpaper was 2.75 meters long.
Answer:
Think
Explanation:
What is the energy of a 478 kg object that is moving with a speed of 15 m/s
I will give you more points!!! :)
But first, answer the question below!!!
Please help, will give brainliest:
The spacecraft OSIRIS-REx is currently orbiting Bennu at an average distance from its center of mass of 1000 meters. At this distance, it takes 24 hours and 57 minutes to complete one orbit. What is its average orbital velocity?
Answer:
v = 0.0251 km/h
Explanation:
Given that,
The average distance from its center of mass of 1000 meters.
The time taken is 24 hours and 57 minutes to complete one orbit
We need to find the orbital velocity of the spacecraft OSIRIS-REx.Let it is v. SO,
[tex]v=\dfrac{2\pi r}{t}[/tex]
Putting all the values,
[tex]v=\dfrac{2\pi \times 100}{24\ hours\ and\ 57\ minutes}\\\\v=\dfrac{2\pi \times 100}{(86400+3420)}\\\\v=0.00699\ m/s[/tex]
or
v = 0.0251 km/h
So, the average orbital velocity is 0.0251 km/h.
calculate your power in watts if you do 500 N*m of work picking up a dumbbell,and takes 5 s to perform that task?
Answer:
100watts
Explanation:
Given parameters:
Workdone = 500Nm
Time taken = 5s
Unknown:
Power in watts = ?
Solution:
Power is the rate at which work is done;
Power =[tex]\frac{workdone }{time}[/tex]
Input the parameters and solve;
Power = [tex]\frac{500}{5}[/tex] = 100watts
Jayden created a cell model using a glass bottle with a cork. He said that the cork could be opened to eliminate waste material that’s generated after digestion in the cell. A number of particles resembling organelles are in the bottle. Which organelle’s function will cause Jayden to open the cork to eliminate waste material?
A. chloroplast
B. cytoplasm
C. nucleus
D. lysosome
E. ribosome
Answer:
D. lysosome
Explanation:
A. chloroplast - the role of the chloroplast is to trap light energy and perform photosynthesis
B. cytoplasm - the cytoplasm is the fluid-filled space inside the cell
C. nucleus - the nucleus houses the genetic material
D. lysosome - This is the correct answer. Lysosomes trap and digest waste products in the cell and break them down into reusable components.
E. ribosome - the ribosomes are protein synthesis machines
The X-axis of a position-time graph represents
Answer:
The motion of an object can be represented by a position-time graph like Graph 1 in the Figure below. In this type of graph, the y-axis represents position relative to the starting point, and the x-axis represents time
Explanation:
If you run east for 38m, stop suddenly, run another 27m east, then you run west for 47
m, what is your total displacement?
how to answer: #m, direction
Answer:
Total Displacement = -18m
Explanation:
Given
East Movement = 38m and 27m
West Movement = 47m
Required
Determine the total displacement
To answer this, we consider east as negative direction and the west as positive (using logics of number line).
Total Displacement = East Movement + West Movement
Total Displacement = -38m - 27m + 47m
Total Displacement = -18m
Hence, the total displacement is 18m towards East
Which of the following is NOT an undefined term?
A. Line
B. Point
C. Line Segment
D. Plane