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.
Which image shows an example of the electromagnetic force in action?
Answer:
the answer is A the one that has the green ball as particles
Explanation:
The second image showing an electromagnet is an example of the electromagnetic force in action therefore the correct option is B
What is electromagnetic force?It is a type of force that occur between electrically charged particles. The electromagnetic force is the combination of all the electrical and magnetic forces generated from any charged particle,
These electromagnetic forces either be attractive or repulsive.
The force generated from a simple bar magnet is an example of the electromagnative force, hence the correct option is B
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which of the following is the same as 1 second
Answer:
theres no
Explanation:
picture or anything so... ur question doesnt make sense
Which of the following describes an ionic compound (or what is true for ionic compounds)?
a. It has a low melting points
b. It consists of shared electrons
c. It conducts electric current in water solution
d. It consists of two non-metals
Answer:
a b c
Explanation:
b. It consists of shared electrons
c. It conducts electric current in water solution
d. It consists of two non-metals
What are Ionic compound?Ionic compounds are neutral compounds made up of positively charged ions called cations and negatively charged ions called anions.
For binary ionic compounds (ionic compounds that contain only two types of elements), the compounds are named by writing the name of the cation first followed by the name of the anion.
The properties of ionic compound are:
They form crystals. They have high melting points and high boiling points.They have higher enthalpies of fusion and vaporization than molecular compounds.They are hard and brittle.They conduct electricity when they are dissolved in water.They are good insulators.They consist of two non metals.Therefore,
b, c, d are the correct answer.
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As the concentration of greenhouse gases in the atmosphere increases, Question 2 options: a) less energy is trapped, which leads to a decrease in Earth's global temperature b) more energy is trapped, which leads to a decrease in Earth's global temperature c) more energy is trapped, which leads to an increase in Earth's global temperature d) less energy is trapped, which leads to an increase in Earth's global temperature
Answer:
c) more energy is trapped, which leads to an increase in Earth's global temperature
Explanation:
Greenhouse effect is caused by the trapping of the reflected energy from the surface of the earth into the atmosphere by some gases. Thus with time causes more energy to be trapped in the atmosphere, which cause an increase in the average ambient temperature of the earth. Because the energy could not escape out into space beyond the earth's atmosphere. Therefore, an increase in Earth's global temperature.
So that the correct option in the given question is C.
compare and contrast speed and strength
Answer:
Down Below
Explanation:
As nouns the difference between speed and strength
is that speed is the state of moving quickly or the capacity for rapid motion; rapidity while strength is the quality or degree of being strong.
Answer:
Explanation:is that speed is the state of moving quickly or the capacity for rapid motion; rapidity while strength is the quality or degree of being strong.
Help PLZ ;)
Which of the following statements is true about the force of gravity:
(A)The Force of gravity between two objects is directly related to the mass of the largest object.
(B)The force of gravity between two objects is directly related to the product of the object’s masses.
(C) The force of gravity between two objects is inversely related to the mass of the largest object.
(D) The force of gravity between two objects is inversely related to the product of the object’s masses.
Answer:
I believe it qould be A) The Force of gravity between two objects is directly related to the mass of the largest object.
Explanation:
23. A ball is dropped from 215m. How long will it take to reach the ground?
Answer:
6.6 s.
Explanation:
From the question given above, the following data were obtained:
Height (h) = 215 m
Time (t) =..?
Thus, we can obtain the time taken for the ball to get to the ground by applying the following formula:
h = ½gt²
Where:
h is the height.
g is the acceleration due to gravity
t is the time to taken.
With the above formula, the time taken for the ball to get to the ground can be obtained as follow:
Height (h) = 215 m
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =..?
h = ½gt²
215 = ½ × 9.8 × t²
215 = 4.9 × t²
Divide both side by 4.9
215 / 4.9 = t²
Take the square root of both side.
t = √(215 / 4.9)
t = 6.6 s
Therefore, it will take 6.6 s for the ball to get to the ground.
Science
There are five elements of a universal systems model: goal, inputs, processes, outputs, and feedback. Which of the following describes the "processes" portion of this model?
A. the results of the system
B. information collected from the outputs
C. the money, time, and resources used on the model
D. what is done to the inputs
Answer:
d
Explanation:
Answer:
the answer is C. The money time and resources used on the model
Explanation:
Why should you never do an exercise such as the bench press without a spotter?
Answer:
you could hurt yourself
Explanation:
Answer
You should never do an exercise such as the bench press without a spotter because you could hurt yourself or push your self too much.
Explanation:
Typically in hot weather or when a person’s muscles heat up, a person can produce more________ than normal. IT’S P.E WORK!
Answer:
Sweat. Hope this helps!!
Explanation:
A skier (down a straight course) is able to enter the starting gate with a speed of 1 m/sec and the average acceleration down the hill was 3 m/s2. If
the skier covers the course in 10 sec, how fast was he moving at the bottom of the course?
O31 m
O 13 m/s
O-29 m/s
O 31 m/s
If a skier (down a straight course) is able to enter the starting gate with a speed of 1 m/sec and the average acceleration down the hill was 3 m/s², then he was moving at 31 m / s at the bottom of the course.
What are the three equations of motion?There are three equations of motion given by Newton
v = u + at
S = ut + 1/2 × a × t²
v² - u² = 2 × a × s
As given in the problem, a skier (down a straight course) is able to enter the starting gate with a speed of 1 m/sec and the average acceleration down the hill was 3 m/s² .
By using the first equation of the motion,
v = u + at
v = 1 + 3 × 10
v = 31 m / s
Thus, he was moving at 31 m / s at the bottom of the course.
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Suppose a boat moves at 12.0m/s relative to the water. If the boat is in a river with the current directed east of 2.50m/s, what is the boat's speed relative to the groiund when it is heading (a) east, with the current, and (b) west, against the current?
Answer:
(a) 14.5 m/s
(b) 9.5 m/s
Explanation:
Let the speed of the boat in the still water (i.e relative to ground) is [tex]v_0[/tex].
Given that the speed of the boat relative to water, [tex]v_r=12.0[/tex] m/s.
Speed of the water current of the river relative to the ground, [tex]u_0=2.50[/tex] m/s towards east.
(a) When the boat is heading toward the east (in the same direction of the current of the river)
The relative velocity, [tex]v_r[/tex], of the boat with respect to ground is
[tex]v_r=v_0-u_0[/tex]
[tex]\Rightarrow 12=v_0-2.5[/tex]
[tex]\Rightarrow v_0=12+2.5=14.5[/tex] m/s
Hence, the boat's speed relative to the ground when it is heading east, with the current, is 14.5 m/s.
(b) When the boat is heading toward the west (in the opposite direction of the current of the river)
The relative velocity, [tex]v_r[/tex], of the boat with respect to ground is
[tex]v_r=v_0-(-u_0)[/tex]
[tex]\Rightarrow 12=v_0+2.5[/tex]
[tex]\Rightarrow v_0=12-2.5=9.5[/tex] m/s
Hence, the boat's speed relative to the ground when it is heading west, against the current, is 9.5 m/s.
HELP PLEASE!!! 15 POINTS
How does the speed of waves vary in different media?
Radio waves are used to transmit verbal messages through space.
IS THIS TRUE OR FALSEE???
A force applied to a 0.25 Kg hockey puck gives the puck an acceleration of 16 m/s2. What acceleration would the same force give to a 0.50 Kg baseball?
Answer:
8 m/s².
Explanation:
We'll begin by calculating the force applied to 0.25 Kg hockey puck. This is illustrated below:
Mass (m) = 0.25 Kg
Acceleration (a) = 16 m/s²
Force (F) =.?
Force (F) = mass (m) × acceleration (a)
F = ma
F = 0.25 × 16
F = 4 N
Therefore, a force of4 N was applied to the 0.25 Kg hockey puck.
Finally, we shall determine the acceleration in which the 4 N force will give to the 0.50 Kg baseball. This can be obtained as follow:
Mass (m) = 0.50 Kg
Force (F) = 4 N
Acceleration (a) =?
F = ma
4 = 0.5 × a
Divide both side by 0.5
a = 4 / 0.5
a = 8 m/s²
Therefore, the same force (i.e 4 N) applied to the hockey puck will give the 0.5 kg baseball an acceleration of 8 m/s².
A force of 75 N at an angle of 15° to the direction of motion moves a chair 3 m. Which change would result in more work being done on the chair?
using 60 N of force
moving the chair 2 m
increasing the angle to 20°
decreasing the angle to 10°
Answer:
decreasing the angle to 10°
Explanation:
correct on edge~ !
Answer:
Decreasing the angle to 10
Explanation:
When the force is calculated it is greater
Explain how if a solid, liquid, and gas are put into individual containers how they fill the container.
Answer:
serial in which container is filled
Solid -base of container
Liquid- above solid
Gas- above liquid
Explanation:
If any mixture of matter in different state (that solid , liquid or gas )are kept in any container, then substance with higher density will be settled at lowest surface first and similarly the substance with lowest density will be at upper part of container.
In the given container we have to keep solid, liquid and gas
sold has the highest density,gas the lowest density andliquid has the density higher than gas but less than solid.based on this
solid will be at surface of container
above sold will be liquid
above liquid will be presence of Gas
serial in which container is filled
Solid -base of container
Liquid- above solid
Gas- above liquid
When the white ball strikes the other colored balls, what can you say about the total momentum of all of the balls combined?
Momentum is never created or destroyed. It is conserved.
The cue stick gave the cue ball all the momentum there is on the table. There's nothing on the table that can pour in any more momentum.
After the strike, with 15 or 16 balls rolling every which way around the table, the total momentum of all of them combined will be the same as the cue ball's momentum right now, before the strike.
When a television is turned on, it converts electrical energy into many other forms of energy. Choose all that correctly lists most of these forms.
Sound
Light
Heat
Electricity
Answer:
sound energy and electricity energy
A space shuttle orbits Earth at a speed of 21,000 km/hr. How far will it travel in 5 hours?
Answer:
105000km
Explanation:
Given parameters:
Speed of shuttle = 21000km/hr
Time of travel = 5hrs
Unknown:
The distance covered by the space shuttle;
Solution:
Distance is the length of the path traveled.
Distance = speed x time
Input the parameters and solve;
Distance = 21000km/hr x 5hrs
Distance = 105000km
Find the acceleration of a car with a mass of 1,200kg and a force of 11,000N
Answer:
42000N
Explanation:
.........................
car decelerates uniformly and comes to a stop after 10 s. The car's average velocity during deceleration was 50 km/h. What was the car's deceleration while slowing down?
Help!!!!
Answer:
[tex]a=-1.388\ m/s^2[/tex]
Explanation:
Initial velocity of car, u = 50 km/h = 13.88 m/s
It stops, v = 0
Time, t = 10 s
We need to find the car's deceleration while slowing down. As the car is slowing down, it will have deceleration. It can be calculated as follows :
[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{0-13.88 }{10}\\\\a=-1.388\ m/s^2[/tex]
So, the deceleration of the car is [tex]1.388\ m/s^2[/tex].
how does a distance-time graph show you which direction the runner is moving? Use your own words and science vocabulary.
Please help will give brainliest to whoever does a 4 setence answer
In a distance time graph, when the x and y values are positive (in first quadrant), the runner is moving forward.
While, if the distance value ( in the y axis) is negative, the runner is moving backwards ( towards the start) .
Hope it helps :)
A distance-time graph shows how far an object has travelled in a certain time. This is a simple line graph that plots observations by distance versus time.
The distance is transferred to the Y axis.
Time is plotted on the X-axis.
The distance-time graph when we study the motion of bodies. If you set the distance and time of the movement of the object and transfer the same data to a rectangular graph, you will get a distance-time graph corresponding to the movement of the object.
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plzzzzzzzzz I need to know for school!!!
What is the definition of law of conservation of energy???
Answer:
This law, first proposed and tested by Émilie du Châtelet, means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another. For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes.
Explanation:
Answer:
Hi! I am confused
Explanation:
Which dwarf planet orbits the Sun far beyond Pluto, taking 560 years per orbit?
Answer:
Eris
Explanation:
The object, temporarily designated 2003UB313 and later named Eris, orbits the sun about once every 560 years, its distance varying from about 38 to 98 AU.
Answer:
me
Explanation:
What are stars? Are their lights natural what is the biggest galaxy are there any other planets other then ours have scientists found the other proofs of Aliens.
Best Answer will get brainliest and gifted points
Answer:
Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. Aside from our sun, the dots of light we see in the sky are all light-years from Earth.
Explanation:
Stars are the most widely recognized astronomical objects, and represent the most fundamental building blocks of galaxies. The age, distribution, and composition of the stars in a galaxy trace the history, dynamics, and evolution of that galaxy. Moreover, stars are responsible for the manufacture and distribution of heavy elements such as carbon, nitrogen, and oxygen, and their characteristics are intimately tied to the characteristics of the planetary systems that may coalesce about them. Consequently, the study of the birth, life, and death of stars is central to the field of astronomy.
Stars are born within the clouds of dust and scattered throughout most galaxies. A familiar example of such as a dust cloud is the Orion Nebula. Turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. As the cloud collapses, the material at the center begins to heat up. Known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star. Three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs; this would explain why the majority the stars in the Milky Way are paired or in groups of multiple stars.
Answer:
stars are are giant balls of gases...yes their light is natural, it emits light due to chemical activities in the cor of star. We are living in the milky way and the nearest galaxy to us is Andromeda galaxy which is about 2.5x more larger than our galaxy, no there are no proofs for presence of aliens
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Describe the nucleus of the atom.
Answer:
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger Marsden gold foil experiment. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the electron cloud.
How can Newton's third law describe the forces affecting a rocket as it
descends to Earth's surface?
A. The rocket pushes through the air with a force equal to that of
Earth's gravity pulling on the rocket.
B. The maximum amount of force the rocket engines can provide
determines how much mass the rocket can lift.
C. The force the rocket exerts on the air is in the direction opposite to
the force that the air exerts on the rocket.
D. The rocket can move downward because the forces acting on it
are unbalanced.
Answer:
C
Explanation:
The force the rocket exerts on the air is in the direction opposite to
the force that the air exerts on the rocket.
Newton's third law describe the forces affecting a rocket as it descends to Earth's surface because: C. The force the rocket exerts on the air is in the direction opposite to the force that the air exerts on the rocket.
Newton's Third Law of Motion states that for every action there exist an equal but opposite reaction.
This ultimately implies that, Newton's Third Law of Motion is a law that is generally based on action-reaction force pairs.
Generally, action-reaction force pairs make it possible for;
Birds to fly.Kicking a ball.Rowing a banca.Cars to move.Objects being in motion.Fishes to swim.Throwing a stone.Rockets descending to Earth's surface.Based on Newton's Third Law of Motion, the force a rocket exerts on the air is in the direction opposite to the force that the air exerts on the rocket.
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A skydiver jumps from an airplane traveling 120. km/hr at a height of 1000. m. If his parachute must open 500. m above the ground, how long does he have for the chute to open?
Answer:
The parachute to open in 15 sec.
Explanation:
Given that,
Velocity = 120 km/hr
Height = 1000 m
If his parachute must open 500. m above the ground.
We need to calculate the time for parachute to open
Using formula of time
[tex]v=\dfrac{d}{t}[/tex]
[tex]t=\dfrac{d}{v}[/tex]
Where, d = distance
t = time
v = velocity
Put the value into the formula
[tex]t=\dfrac{500}{120\times\dfrac{5}{18}}[/tex]
[tex]t=15\ sec[/tex]
Hence, The parachute will be open in 15 sec.
A mover applies a net force of 28 N to a sofa that has a mass of 70 kg.
What will the sofa's acceleration be?
Answer: .4 m/s^2= acceleration
Explanation:
f = m*a
We can rearrange this equation to solve for acceleration. Therefore,
a=f/m
a= 28N/70kg
a= 0.4 m/s^2
Which statements describe why organisms are classified? Check all that apply.
Answer:
what are the options for me