Answer:
25g
Explanation:
According to a quick internet search, the half-life of I-131 is 8 days.
The amount left after 16 days can be calculated with the radioactive exponential decay formula:
[tex]A_(_t_)=A_0e^(^\frac{\ln(.5)}{T}^)^t[/tex]
Where:
[tex]A_(_t_)[/tex] = the amount left as a function of time
[tex]A_0[/tex] = the original amount (100g)
T = the half-life of the isotope (8d)
t = time (16d)
So:
[tex]A_(_t_)=A_0e^(^\frac{\ln(0.5)}{T}^)^t\\A_(_t_)=(100g)e^(^\frac{\ln(0.5)}{8d}^)^(^1^6^d^)\\A_(_t_)=(100g)e^-^2^(^\ln(2))[/tex]
[tex]A_(_t_)=25g[/tex]
This answer is intuitive because the isotope has been through two half-lives:
[tex]100g(\frac{1}{2})(\frac{1}{2})=25g[/tex]
A pencil rolls across a table toward its edge. In one to two sentences, explain which direction the pencil will move once it leaves the table and why.
Answer:
it won't move unless it has momentum
Explanation:
A cheetah can run from 0 to 70 mph in 2.2 seconds. How much distance did the cheetah cover in traveling from 0 to 70 mph?
The top speed of a cheetah in m/s is 31.29 m/s.
Given data:
The initial speed of a Cheetah is, u = 0 mph.
The final speed of the Cheetah is, v = 70 mph.
The time interval is t = 2.2 seconds.
We are already given with top speed of a Cheetah, and it’s none other than the final speed itself. Now we need to convert the mph value of top speed into m/s value.
We know that,
1 mph = 0.44704 m/s
So, the value of 70 mph in m/s is,
Thus, we can conclude that the top speed of a cheetah in m/s is 31.29 m/s.
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Suppose you need to design a parachute system to help a remote camera land safely at the bottom of a cave. The camera will drop from a height of one story. It has a mass of about 500 g. A carton of eggs inside a box will model the camera. For your test to be successful, none of the eggs can break when the box lands. You may use string, plastic bags, paper, and any fabrics you have to make a model parachute.
Identify the criteria and constraints. Describe your model and draw a picture of it. Describe how you could test your model and what you would do after the first test.
(pls make don't talk about high school)
The criteria for a successful parachute system are that it must be able to safely land the camera without breaking any of the eggs. The constraints are that the parachute must be made using only string, plastic bags, paper, and fabrics, and the camera must be modeled using a carton of eggs.
One possible model for the parachute system could be a square parachute made of paper or fabric, with strings attached to the corners of the parachute. The camera (represented by the carton of eggs) would be attached to the center of the parachute.
To test the model, we could drop the parachute and camera from a height of one story (or a similar height) and observe whether the eggs break upon landing. If the eggs do not break, the parachute system is considered successful.
After the first test, we could make changes to the design of the parachute (such as changing the shape or size, or adding more strings) and test it again to see if it performs better. We could continue making and testing different designs until we find a parachute system that meets the criteria and constraints.
Once the hydrogen in the core of a star runs out, what element does the star begin to fuse
next?
Once the hydrogen in the core of a star runs out, then the element, Helium begins to fuse.
Helium begins to fuse, once the core of a star runs out, as helium is then, the only lightest element left in the core of the star.
The energy produced in the fusion processes decreases, as heavier and heavier element starts to fuse. Stars become the main sequence stars after they fuse hydrogen.
Once the hydrogen in the core runs out, the stars could not hold against gravity more, thereby increasing the pressure and temperature in the core of the star.
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The coefficient of kinetic friction between an object and the surface upon which it is sliding is 0.40 the weight of the object is 4.2
The frictional force of an object is the product of the normal force and coefficient of kinetic friction. Here the frictional force acting on the object is 16.4 N.
What is frictional force?
Frictional force is a kind of force acting on a body to resist it from motion. Thus, the direction of the force will be in negative with the magnitude. Frictional force is the product of coefficient of friction and the normal force.
The normal force acting on the object of mass 4.2 Kg is N = mg
N = 4.2 Kg × 9.8 m/s² = 41.16 N
Frictional force = ц N
= 0.40 × 41.16 N
= 16.4 N.
Therefore, the frictional force acting between the surface of the object and the floor is 16.4 N
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Your question is incomplete. But your complete question probably was:
The coefficient of kinetic friction between an object and the surface upon which it is sliding is 0.40 the weight of the object is 4.2 kg. What is the frictional force of the object?
Baseballs aren’t especially bouncy. A baseball fired at 20 m/s
at a solid wall rebounds at 11 m/s. What fraction of the initial kinetic energy is transformed into thermal energy?
The fraction of the initial kinetic energy is transformed into thermal energy is 3/4.
What fraction of the initial kinetic energy is transformed into thermal energy?The fraction of the initial kinetic energy is transformed into thermal energy is calculated by applying the principle of conservation of energy as shown below.
Mathematically, this is given as;
ΔK.E = E
where;
ΔK.E is the change in kinetic energyE is the thermal energyE = K.Ef - K.Ei
where;
K.Ef is the final kinetic energyK.Ei is the initial kinetic energyE = (¹/₂mu² - ¹/₂mv²) / (¹/₂mu²)
where;
m is the mass of the baseballv is the final velocity of the baseballu is the initial velocity of the baseballE = (u² - v²) / (u²)
E = (20² - 10²) / (20²)
E = 0.75 = 3/4
Thus, the fraction of the initial kinetic energy is transformed into thermal energy is a function of the change in speed of the baseball.
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please someone help its due soon
Answer:
it would be 80 would it not
Explanation:
The 40 is just the angle to the normal ray. just multiply it by two giving you 80
The net force acting on Mrs. Cosce 1,500 kg car is 12,000 N. What is the acceration of her car?
Answer: 8.0 m/s2
Explanation:
F = ma
a = F/m
F = 12,000 N
m = 1,500 kg
a = 12,000 N / 1,500 kg = 8.0 m/s2
Are the results of the investigation described below valid? If not, what should the scientists do next? Explain your reasoning.
Passage A scientist wrote a report that communicates the steps he performed in an investigation, the data he gathered, and his conclusions. A second scientist used the report to carry out the same investigation. However, her results were very different.
In the case described above, there are at least three possible scenarios:
The first research or experiment was correct but wrongly documentedThe first experiment was correct and correctly documented; andThe second research was not properly executed according to the documentation of the first researcher.In any of the above cases, the correct step to take, if it is possible is for both scientists to meet, review notes and jointly execute a third investigation. This is because, in science, the guesswork only happens during hypothesis formulation.
Once a principle has been established via experimentation and properly documented, the same research can be replicated in any other location by any other person with the end results being the same if they all follow the exact report documented when the investigation was deemed successful.
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3. A beach ball is inflated to a volume of 25L of air at 15°C. During the afternoon,
the volume increases by 1L. What is the new temperature outside?
Answer:
Below
Explanation:
P1V1/T1 = P2V2/T2 T MUST be in Kelvin
P1 = P2 so this becomes
V1/T1 = V2/T2
25/ (273.15 + 15) = 26 / (273.15 + X) where 'X' is the °C afternoon temp
X = 26.5 °C
3. A bald eagle in level flight at a height of 135m drops the fish it caught. If the eagle's
speed is 25.0 m/s how far from the drop point will the fish land?
The horizontal distance travelled by the fish when dropped is 131.25 m.
What is the time of motion of the fish?
The time of motion of the fish from the given height is calculated by applying the following kinematic equation as shown below.
h = vt + ¹/₂gt²
where;
v is the initial vertical velocity = 0t is the time of motion'g is acceleration due to gravityh = 0 + ¹/₂gt²
t = √ ( 2h / g )
t = √ ( 2 x 135 / 9.8 )
t = 5.25 seconds
The horizontal distance travelled by the fish when dropped is calculated as;
X = vt
X = 25 m/s x 5.25 s
X = 131.25 m
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If the potential energy is 2000 J with a mass of 7 kg, what is the height of the object?
Answer: Height of object = 29.13475
Hope this helps!
Answer: 29.12 Meters.
Explanation:
Potential energy = Mass * Gravity * Height. | (P=mgh)Rearrange the equation for height: H=(p/(g*m))Place the values: H=(2000J)/(9.81 * 7kg)Answer equals 29.12MA sound pulse emitted underwater reflects off a school of fish and is detected at the same place 0.10 s later. How far away are the fish? (Assume the water temperature is 20 degrees C.)
The distance of the fish, given that a sound pulse was heard 0.10s later is 148.1 m
How do I determine the distance of the fish?Speed is related to distance according to the following formula:
Speed = distance / time
Cross multiply
Distance = speed × time
Using the above formula, we can determine the distance of the fish. Details below:
Speed of sound in fresh water at 20 °C = 1481 m/sTime = 0.10 secondDistance of fish =?Distance = speed × time
Distance = 1481 × 0.10
Distance = 148.1 m
Thus, we conclude that the distance of the fish is 148.1 m
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What is the biggest agent of erosion?
a tornadoes
b pollution
c gravity
d water
Answer:
D - Water
Explanation:
Part A
Find the water pressure at the bottom of the 54-m-high water tower in the following figure.
Express your answer to two significant figures and include the appropriate units.
Incorrect; Try Again; 5 attempts remaining
Enter your answer with a different unit type. Review a list of acceptable units.
The water pressure at the bottom of the 54-m-high water tower is
0.53 M Pa0.53 M N/m²How to calculate the pressure of waterpressure of water at a certain depth is calculated using the formula
Pressure, P = height * density * acceleration due to gravity
density of water is given by = 1000 kg/m³
acceleration due to gravity is given by = 9.82 m/s²
the given height, at the bottom of the 54-m-high water tower = 54 m
Pressure = 1000 kg/m³ * 9.82 m/s² * 54 m
Pressure = 530280 N/m²
Pressure = 0.53 M N/m²
Pressure = 0.53 M Pa
The pressure at the bottom of the 54-m-high water tower is 0.53 MPa
The unit of pressure used here is Pa which is equal to N/m² other unit include pound - force foot
1 N/m² = 0.73756 pound-force foot
530280 N/m² = 530280 * 0.73756 = 391113.32 pound-force foot
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If you are running at 6m/s and decide at 2m/s². How long will take you to stop and how far will You go respectively while declaration
You will take 3 second to stop and you will go 9 meters far.
What is velocity?
The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.
Given that:
Initial velocity: u = 6 m/s.
deceleration: a = 2 m/s^2.
Final velocity = 0 m/s.
We have to find: time: t = ? and distance travelled: s = ?
So, time taken to stop = v/a = 6/2 second = 3 second.
Distance travelled in this process: s = v^2/2a = (6×6)/(2×2) meter = 9 meter.
Hence, you will take 3 second to stop and you will go 9 meters far.
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A gardener is driving a lawnmower with a force of 80N that makes an angle of 40° degree with the ground find its horizontal component
The horizontal component of force be 61.28 N.
What is force?The definition of force in physics is: The push or pull on a massed object changes its velocity.
An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude. The application of force is the location at which force is applied, and the direction in which the force is applied is known as the direction of the force.
Given that:
A gardener is driving a lawnmower with a force of 80N that makes an angle of 40° degree with the ground.
So, horizontal component of force be = 80 cos40° N = 61.28 N.
Hence, the horizontal component of force be 61.28 N.
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If you are running at 6m/s and decide at 2m/s². How long will take you to stop and how far will You go respectively while declaration
It will take 3 sec to stop at the distance of 9 m while declaration.
What is declaration?Deceleration was actually inversely related to acceleration. We know that acceleration means the speed at which the object is accelerating, and deceleration means the speed at which the object is decelerating. For example, when you brake while driving, deceleration is used to slow the vehicle. This is represented by -a. where a is the acceleration.
Time taken to stop:
-a = (v-u)/t
-2 = (0-6)/t
t = -6/2
t = 3 sec.
Distance travelled during this process:
v² = u² + 2as
Since, v =0
s = u²/2a
= (6×6)/(2×2)
= 9 m
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How many seconds would it take a Dalmatian to accelerate from rest to its
top speed of 16.5 m/s over a distance of 11 meters?
It take 1.33 second to a Dalmatian to accelerate from rest to its top speed.
What is acceleration?Acceleration is rate of change of velocity with time. Due to having both direction and magnitude, it is a vector quantity. Si unit of acceleration is meter/second² (m/s²).
given parameters:
initial speed, u = 0
final speed, v =16.5 m/s.
distance covered, s = 11 meters.
We have to find: time t = ?
We know that:
s = ut +(v-u)t/2
⇒ 11 = 0 + (16.5 -0)t/2
⇒ t = 22/16.5 second = 1.33 second.
So, it take 1.33 second to a Dalmatian to accelerate from rest to its top speed.
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SECTION IV
QUESTION: 2. On the football field, a 95-kg halfback makes a turn. The halfback
sweeps out a path that is a portion of a 12-meter-radius circle. If in 2.1 seconds, the
halfback completes a quarter-circle turn. Determine the halfback's speed and
acceleration.
Pls solve this
Answer:
Speed = (2πr)/t = (2π x 12 m)/2.1 s = 28.6 m/s
Acceleration = (vf-vi)/t = (28.6 m/s - 0 m/s)/2.1 s = 13.6 m/s^2
No no no no. no no no no
A dryer uses electrical energy to spin a drum and produce heat. It uses 220 V of an electric charge and 50 A of electric current. What is the dryer power?
The power used by the dryer to spin the drum and produce heat is 11000 Watts.
What is the power of the dryer?Power is simply the quantity of energy transferred per unit time.
This is expressed as;
P = v × I
Where v is voltage and I is current.
Given that;
Voltage v = 220VCurrent I = 50APower P = ?Plug the given values into the above formula and solve for P.
P = v × I
P = 220V × 50A
P = 11000 Watts
Therefore, the power used by the dry is 11000 Watts.
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Suppose the charges attracting each other in the above situation have an equal magnitude. Find the charge.
The situation- Two-point charges are separated by 6 cm. The attractive force between them is 27 N. Find the force between them when they are separated by 18 cm. (Why can you solve this problem without knowing the magnitudes of the charges?) i got 6.75 if the answer is needed
The force between the two point charge when they are separated by 18 cm is 3 N
How do I determine the force when they are 18 cm apart?Coulomb's law states as follow:
F = Kq₁q₂ / r²
Cross multiply
Fr² = Kq₁q₂
Kq₁q₂ => constant
F₁r₁² = F₂r₂²
Where
F₁ and F₂ are the initial and new forcer₁ and r₂ are the initial and new distance apartWith the above formula, we can obtain the force between the two point charge when they are 18 cm apart. Details below:
Initial distance apart (r₁) = 6 cmInitial force of attraction (F₁) = 27 NNew distance apart (r₂) = 18 cmNew force of attraction (F₂) =?F₁r₁² = F₂r₂²
27 × 6² = F₂ × 18²
972 = F₂ × 324
Divide both side by 324
F₂ = 927 / 324
F₂ = 3 N
Thus, the force when they are 18 cm apart is 3 N
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The reasoning developed for counting microstates applies to many other situations involving probability. For example, if you flip a coin 5 times, how many different sequences of 3 heads and 2 tails are possible? Answer: 10 different sequences, such as HTHHT or TTHHH. In contrast, how many different sequences of 5 heads and 0 tails are possible? Obviously only one, HHHHH, and our equation gives 5!/[5!0!]=1, using the standard definition that 0! is defined to equal 1 If the coin is equally likely on a single throw to come up heads or tails, any specific sequence like HTHHT or HHHHH is equally likely. However, there is only one way to get HHHHH, while there are 10 ways to get 3 heads and 2 tails, so this is 10 times more probable than getting all heads. Use the expression 5!|[N!(5−N)!] to calculate the number of ways to get 0 heads, 1 head, 2 heads, 3 heads, 4 heads, or 5 heads in a sequence of 5 coin tosses. Make a graph of the number of ways vs. the number of heads.
Answer:
Explanation:
10 different sequences
mr wang works in a recycling center recyclable materials arrive at the center mixed together workers use magnets separate steel cans from other items which two statements are true about the force between a steel can and a magnet
The force between the magnet and the can is the noncontact force. The attraction between the magnet and the can is a pull. Therefore, option B and C are correct.
What is a magnet?A magnet can be described as a material that produces a magnetic field and this magnetic field is responsible for the properties of a magnet. The properties magnet is such a force that pulls ferromagnetic materials, such as steel, iron, cobalt, etc., towards it.
A permanent magnet can be described as an object made of a material that can be magnetized and creates its own magnetic field. These type of materials are strongly attracted to a magnet, is known as ferromagnetic, and consist of the elements iron, nickel, and cobalt.
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Your question was incomplete, most probably the complete question was,
Mr. wang works in a recycling center recyclable materials arrive at the center mixed together workers use magnets to separate steel cans from other items which two statements are true about the force between a steel can and a magnet:
A) Gravity pushes the can toward the magnet.
B) The force between the magnet and the can is the noncontact force.
C) The attraction between the magnet and the can is a pull
D) The attraction between the magnet and the can is a push.
Which of the position versus time graphs below matches the following description: a speed versus time graph has a horizontal line at 5 m/s from zero to five seconds?
The position versus time graph that matches the description: a speed versus time graph has a horizontal line at 5 m/s from zero to five seconds is Graph A; The correct option is A.
What is a position versus time graph?A position versus time graph is a graph that plots the position of an object against the time it takes for the object to move from one point to another.
The slope of a position versus time graph represents the speed or velocity of the object.
The slope of a position time graph = distance or position/time
A speed versus time graph is a graph that plots the speed of an object against the time it takes for the object to move to that speed.
The slope of a position versus time graph represents the acceleration of the object.
Considering the given speed versus time graphs:
Graph A: the speed versus time graph has a horizontal line at 5 m/s from zero to five seconds.
Graph B: the speed versus time graph shows variation is speed over time
Graph C: the speed versus time graph shows a constant increase in speed over time
Graph D; the speed versus time graph shows a constant decrease in speed over time
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A 230,000 V-rms power line carries an average power PAV = 250 MW a distance
of 200 km. If the total resistance of the cables is 10 ohms, what is the resistive
power loss?
a. 1.0 MW
b. 2.5 MW
c. 5.4 MW
d. 12 MW
e. 10 kW
The power loss over the given distance in which the current is carried is 12 MW.
option D is the correct answer.
What is the current carried in the power line?
The current carried in the power line is calculated by applying Ohms law as follows;
V = IR
P = IV
I = P/V
where;
P is the average power of the lineV is the voltageI is the currentI = (250 x 10⁶) / (230,000)
I = 1,086.96 A
The power loss over the given distance in which the current is carried is calculated as;
P = I²R
where;
R is the resistance of the wireP = (1,086.96²) x 10
P = 11.8 x 10⁶ W
P ≈ 12 x 10⁶ W
P = 12 MW
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Two crates, 10 kg and 15 kg respectively, are connected with a thick rope according to the diagram. A force, to the right, of 500 N is applied. The boxes move with an acceleration of 2 m/s^2 to the right. One third of the total frictional force is acting on the 10 kg block and two thirds on the 15 kg block. Calculate: the magnitude and direction of the total frictional force present.
Explanation:
Total frictional force = 500 N
Magnitude of frictional force on 10 kg block = 500 N/3 = 166.67 N
Magnitude of frictional force on 15 kg block = 500 N/3 x 2 = 333.33 N
Direction of frictional force on 10 kg block = Left
Direction of frictional force on 15 kg block = Left
A bus slows down from 8.22 m/s to a stop in 13.3 s. Its wheels have a radius of 0.530 m. Find the initial angular speed of the wheels.
Answer:
The initial angular velocity of the bus wheel:
ω₀ ≈ 15.6 rad / s
Explanation:
Given:
V₀ = 8.22 m/s - Starting speed of the bus
V= 0 m/s - Final speed of the bus (the bus has stopped)
ω = 0 rad/c - Final angular velocity of the bus wheel
t = 13.3 s - Bus deceleration time
R = 0.530 m - Bus wheel radius
____________________
ω₀ - ? - The initial angular speed of the wheels.
1) Bus linear acceleration module:
a = ( V₀ - V) / t = (8.22 - 0) / 13.3 ≈ 0.62 m/s²
2) Bus angular accelerations module:
ε = a / R = 0.62 / 0.530 ≈ 1.17 rad / s²
3) The initial angular velocity of the bus wheel:
ω₀ = ε·t = 1.17·13.3 ≈ 15.6 rad / s
Explain how the energy from the sun is transferred to fossil fuel?
Answer:
Fossil fuels are energy sources that come directly from nature. First, the sun's radiant energy is stored as chemical energy in plants by photosynthesis. When the plants die, they start decaying. After many years, the plants are turned into fossil fuels.
Explanation:
Fossil fuels rely on the Sun's energy because the energy in fossil fuels came from plants and algae as they performed photosynthesis, which requires sunlight.
When sunlight strikes a plant, some of the energy is trapped through photosynthesis and is stored in chemical bonds as the plant grows.
(u should paraphrase it)