The probability that a randomly chosen nucleus in a radioactive sample will have decayed in a given time is 96.875%. The sample has experienced 5 half lives. The correct option is A.
What is half life?Half life is the time required for the heavy nucleus or any radioactive material to disintegrate by half its quantity.
After one half life, the probability of decay of any nucleus is given by 50%. = 0.5
After two half lives gone, probability of decay is 0.5 + 1/2(0.5) = 0.75
After, three half lives gone, probability of decay is 0.5 + 1/2(0.5) + (1/2)²(0.5) = 0.875
After, four half lives gone, probability of decay is 0.5 + 1/2(0.5) = 0.875 + (1/2)³(0.5) = 0.9375.
After, five half lives gone, probability of decay is 0.9375 + (1/2)⁴(0.5) = 0.96875.
Thus, the sample has experienced 5 half lives. The correct option is A.\
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A flywheel is rotating with an angular velocity of 1.4 rad/s and is acted on by an acceleration of 0.6 rad/s².
a) What angular velocity will it have attained after three complete turns?
b) How long will it take to do those three turns?
(a) The final angular velocity of the flywheel after 3 complete revolutions is 4.96 rad/s.
(b) The time taken for the flywheel to make 3 complete revolutions is 5.93 s.
Final angular velocityThe final angular velocity of the flywheel after 3 complete revolutions is determined by applying third kinematic equation as shown below;
θ = 2π (rad/rev) x (3 rev) = 18.85 rad
ωf² = ωi² + 2αθ
ωf² = (1.4)² + 2(0.6)(18.85)
ωf² = 24.58
ωf = √24.58
ωf = 4.96 rad/s
Time of motionThe time taken for the flywheel to make 3 complete revolutions is calculated as follows;
ωf = ωi + αt
t = (ωf - ωi)/α
t = (4.96 - 1.4)/0.6
t = 5.93 s
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Which condition is necessary for a lunar eclipse to occur?.
For a lunar eclipse to occur, the Sun, Earth, and Moon must be roughly aligned in a line. Otherwise, the Earth cannot cast a shadow on the Moon's surface and an eclipse cannot take place. When the Sun, Earth, and Moon come together in a straight line, a total lunar eclipse takes
A spaceship moves at a constant velocity of 0.400c relative to an Earth observer. The pilot of the spaceship is holding a rod, which he measures to be 1.00 m long. The rod is held perpendicular to the direction of motion of the spaceship. How long is the rod according to the Earth observer
Since the rod is held perpendicular to the direction of motion of the spaceship, the rod is 1.00 m long to an Earth observer.
To answer the question, we use the principle of length contraction in relativity.
What is Length contraction?The principle of length contraction states that the length of an object would only contraction when it is in the direction of motion.
So, since the 1.00 m long rod is in the spaceship is held perpendicular to the direction of motion of the spaceship, there is no length contraction and thus, an observer on the Earth measures the same length of 1.00 m.
So, Since the rod is held perpendicular to the direction of motion of the spaceship, the rod is 1.00 m long to an Earth observer.
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If we say that a galaxy has a lookback time of 1 billion years, we mean that _________.
Answer:
its light traveled through space for 1 billion years to reach us
Explanation:
Copper (II) chloride reacts with magnesium nitride
Answer:
I don't know
Explanation:
because I'm not smart
a roller coaster of mass 2000kg is rolling down a track with an instantaneous speed of 10m/s
The given is:Mass – 2000 kg
The given is:Mass – 2000 kgInstantaneous speed – 10 meter per second
Step: 1Step: 1K.E= 1/2mv^2
Where, K.E – Kinetic energy in joules:
m – Mass in kg
v – Velocity or speed in meter per second
Step: 2From the give,
m = 2000 kg
v = 10 m/s
Equation (1) becomes,
K.E= 1/2 (2000) (10)^2
= (0.5)(2000)(100)
= 100000
K.E = 100,000 Joules
The kinetic energy is 100,000 Joules, if a roller coaster of mass 2000 kg is rolling down a track with an instantaneous speed 10 m/s.
The batteries of some flashlights can be charged by turning a handle. Which energy transformation is happening in this process
The energy transformation that is happening in this process is mechanical energy to chemical energy.
Energy ConversionAccording to conservation of energy, energy can not be distroyed and cannot be created, but can only be transformed from one form to another.
The batteries of some flashlights can be charged by turning a handle. The energy transformation that is happening in this process is mechanical energy to chemical energy. The chemical energy will transform to electrical energy which will eventually transform to light energy.
The turning of the handle is mechanical and the energy in battery is chemical.
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Since many wavelengths of light are measured in nanometers, it's useful to know that planck's constant (h) multiplied with the speed of
light (c) is equal to 1240 eVnm.
This is useful, as E = hf, or otherwise written as E= .
With this information in mind, solve the following:
A photon has 1.6 eV of energy. What is the wavelength of this photon?
O a
410 nm
Ob
775 nm
Ос
1984 nm
Od
306 nm
Answer:
E = h f and since f = c / λ we have E = h c / λ
Thus λ = h c / E
Also, 1 ev = 1.6E-19 C
λ = 6.63E-34 * 3.0E8 / (1.6 * 1.6E-19)
λ = 6.63 * 3.0 / (1.6 * 1.6) * E-7
λ = 7.77E-7 = 777 nanometers
(B) is correct
You serve a volleyball with a mass of 2.1kg the ball leaves your hand with a speed of 30 m/s. What is the kinetic energy of the ball?
Answer:
945 joules
Explanation:
the formula for kenetic energy is:
0.5 × m × v^2
where m is in (kg) ane (v) is in meter per second.
so we can just use the formula;
0.5 × 2.1 × 30^2
so the answer is 945 joules
Which sound frequency could a human detect? 1 hertz 10 hertz 50 hertz 50,000 hertz.
Answer:
Good human ears can detect sound from about 50 Hz to about 20,000Hz (20 kHz); this can be called the audible range of frequencies.
so c.50 hertz
Explanation:
Hope it helps :)
Answer:
50 hertz
Explanation:
This is right
PLEASE SOMEONE HELP!! what is the answer? WILL MARK BRAINLIEST!!
Answer:
A.
Explanation:
The answer should be A.
i apologize if it is incorrect-
I hope it helps! Have a great day!
Anygays-
Which of these invertebrates have asymmetric bodies?
Answer:
Sponges
Explanation:
It would be either sponges or flatworms.
I apologize if it is incorrect-
I hope it helps! Have a great day!
Anygays-
How much work can a 1000-watt motor do in 5.0 seconds?
A. 4.0 × 101 J
B. 2.0 × 102 J
C. 5.0 × 103 J
D. 2.5 × 104 J
Answer:
C
Explanation:
watt = j/sec and work = j
so multiply watt * sec to get work
1000 j/sec * 5 sec = 5000 j = 5 x 10^3
1. Dylan claims that the vase would achieve a higher height if it were launched at a 45-degree angle. Is
Dylan correct?
A. Dylan is correct because a 45-degree launch angle results in the largest vertical range.
B. Dylan is correct because larger launch angles result in a smaller vertical range.
C. Dylan is incorrect because a 90-degree and 45-degree larr
tin the same vertical
range.
D. Dylan is incorrect because a 90-degree launch angle resuh
vertical range
How is the duration and intensity of daylight related to the suns apparent path?
Answer:
I dont know but ask a tutor
Explanation:
MOnkey Srry
Which of the following can explains convection?
A.Hot air is less dense than cold air.
B.The wind blow takes place from higher position to lower position
C.The particles in hot air are lighter than those in cold air.
D.The gas pressure of hot air is greater than that of cold air.
E.The particles in hot air move quicker than that of cold air.
Answer:
A) would be the best explanation because hot air is less dense and would rise to the top of a column of air
Question 3 of 20
A crate falling from a plane is part of a closed system that has 24450 J of
mechanical energy. If the kinetic energy of the crate increases from 10,000 J
to 15,000 J, what happens to the gravitational potential energy of the system?
A. It decreases from 15,000 J to
10,000 J.
B. It increases from 9450 J to
14,450 J.
C. It decreases from 14,450 J to
9,450 J.
O D. It increases from 10,000 J to
15,000 J.
Old potential energy:-
PE+KE=MEPE=ME-KEPE=24450-10000PE=14450JNew potential energy
PE=24450-15000PE=9450JOption B is correct
1. 50 W and 100 W lamps are designed for the same voltage. Which lamp has the higher filament resistance and why?
2. At a voltage of 4 V, 300 mA flows through the bulb. What is the work done by the electric current in 5 min?
3. The label on the lamp says 100 W, 220 V. Calculate the resistance of the lamp?
4. What is the work done by the motor of a floor polisher in 25 min with a voltage of 220 V, a current rating of 1,25 A and a motor efficiency of 80%?
help
Answer:
Look below.
Explanation:
1.) The resistance of a light bulb filament is effected by both length and cross-sectional area. Thicker wires have less resistance. A 120-Watt bulb has a greater current and a smaller resistance. Thus, a 120-Watt bulb must have a thicker filament than a 60-Watt bulb (assuming the lengths of the filaments are identical). We also think of lightbulbs in terms of their power ratings in watts. Let us compare a 25-W bulb with a 60-W bulb. Since both operate on the same voltage, the 60-W bulb must draw more current to have a greater power rating. Thus the 60-W bulb’s resistance must be lower than that of a 25-W bulb. If we increase voltage, we also increase power. For example, when a 25-W bulb that is designed to operate on 120 V is connected to 240 V, it briefly glows very brightly and then burns out. Precisely how are voltage, current, and resistance related to electric power?
2.) Energy transferred = 120 × 2 = 240 J. This equation can be rearranged to V = E ÷ Q. So voltage is energy transferred divided by charge.
3.) Power= Voltage × Current
4.) W=Pt
when a block is made of _____ the cylinders may eventually wear to the point where repairs are ineffective
When a block is made of rough surfaces, the cylinders may eventually wear to the point where repairs are ineffective.
What is Friction?This is the force which occurs when two surfaces slide against each other. A rough surface have more friction than a smooth surface.
Friction causes wearing out of surfaces and may render repair works done ineffective in this case.
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Which terms describe the different movements of earth? check all that apply. rotation revolution tilted orbit lunar cycle elliptical orbit
Revolution and rotation are the terms that describe the different movements of the earth.
What is the earth?Our home planet is Earth. Earth and its moon, according to scientists, originated about the same period as the rest of the solar system.
That would have been around 4.5 billion years ago, according to scientists. Earth is the solar system's fifth-largest planet.
The rotation and revolution of the earth are two different movements. The movement of the earth on its axis is known as rotation.
Revolution is the movement of the earth around the sun in a fixed route or orbit. The earth's axis, which is an imaginary line, forms a 6612° angle with its orbital plane.
Hence revolution and rotation are the terms that describe the different movements of the earth.
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Suppose that your car is stuck on ice. The wheels spin, but the car does not move. Your friend suggests that you let the air out of the tires to increase the amount of friction. What are some reasons your friend might think this? Discuss whether or not these reasons are consistent with what you have learned about friction.
Explanation:
The center of mass of a system acted on only by internal forces cannot accelerate. without friction a car cannot move. This is a consequence of Newton's third law
Please Help Physics!
1. Sound travels through a guitar string at 600 m/s, making a sound wave in the air with a speed of 333 m/s. In 1–2 sentences, explain how the wavelength and frequency of the wave in the string compare to the wavelength and frequency of the wave in the air.
The wavelength and frequency of the sound in the string is greater than the wavelength and frequency of the sound in the air.
Wavelength and freqeuncy of the soundThe wavelength and frequency of the sound is determined using the following formulas.
v = fλ
f = v/λ
λ = v/f
where;
f is the frequency of the soundλ is the wavelengthWavelength and frequency of the sound in the stringf = 600/λ
λ = 600/f
Wavelength and frequency of the sound in airf = 333/λ
λ = 333/f
Thus, the wavelength and frequency of the sound in the string is greater than the wavelength and frequency of the sound in the air.
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How many Watts of power does a model rocket engine have if it does 66 J of work on a model rocket in 0.9 seconds?
Power developed by a model rocket engine will be 73.3 watts. Power is the ratio of the work done or the enrgy to the time period.
What is the power output?The rate of the work done is called the power output. It is denoted by P.Its unit of a watt.
The given data in the problem is;
E is the energy = 66 J
P is the power output =?
t is the time period = 0.9 sec
The power output is given as;
[tex]\rm P = \frac{E}{t} \\\\ \rm P = \frac{66}{0.9} \\\\ \rm P = 73.3 \ watt[/tex]
Hence power developed by a model rocket engine will be 73.3 watts.
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The diagram shows the water levels inside the containers.
A)91 cm
B) 34 cm ( the water levels)
•) The density of water is 1000 kg/m²
ii) Calculate the pressure that the water causes at the base of container A.
Answer:
8927.1 Pa
Explanation:
pressure = height x density of liquid x g
= (91/100) x 1000 x 9.81
= 8927.1 Pa
m=3000km v=25m/s what’s the momentum
Momentum of the given body will be : 75000 Kg m/s
Explanation:According to Newton's first law of motion, all bodies continue to be in the state of rest or motion unless an external force is applied on the body. We can use this in the case of momentum also
The formula of momentum is given by :
[tex]:\implies \sf\quad \sf \: P = mv[/tex]
Here, we are given the mass of the body ( m ) as 3000kg and the velocity of the body ( v ) as 25 m/s. On putting the values in the formula:
[tex] \begin{aligned}&:\implies \sf\quad \sf \: P = mv \\& :\implies \sf\quad \sf \: P = 3000 \times 25 \\ & :\implies \sf\quad \sf \: \boxed{ \sf \: P = 75000kgm {s}^{ - 1} } \end{aligned}[/tex]
Momentum is associated with the mass of the moving body and can be defined as the quantity of motion measured as a product of mass and velocity.
Answer :-
Momentum is [tex] \bf{75,000 \: {kg \: ms}^{ - 1} } [/tex] .Explanation :-
As per the provided information in the given question, we have been given that The Mass is 3000 kg . The Velocity is given as 25 m/s . And, we have been asked to calculate the Momentum .
For calculating the Momentum , we will use the Formula :-
[tex] \bigstar \: \: \: \boxed {\sf { \: Momentum \: = \: Mass \: \times \: Velocity \: }} [/tex]
Therefore , by Substituting the given values in the above Formula :-
[tex] \dag \: \: \: \sf { Momentum \: = \: Mass \: \times \: Velocity} [/tex]
[tex] \Longrightarrow \: \: \: \sf { Momentum \: = \: 3000 \: \times \: 25} [/tex]
[tex] \Longrightarrow \: \: \: \textbf {\textsf {Momentum \: = \: 75000 }} [/tex]
Hence :-
Momentum = [tex] \bf{75,000 \: {kg \: ms}^{ - 1} } [/tex] .[tex] \underline {\rule {180pt} {4pt}} [/tex]
Find the ( mass m ) when system is equilibrium help me pleasee this choice is
1. 4 kg
2. 6.25 kg
3. 10 kg
4. 12.5 kg
5. 25 kg
please show solution
Answer:
5. 25 [kg].
Explanation:
1) the final ratio is:
m_20kg *g=m*g/cos37°; ⇒ m= m_20kg / cos37°;
2) answer is:
m=20/0.8=25 [kg].
Adaptations are unique traits developed by organisms to help them survive, thrive, and reproduce in their particular environment. Adaptations may be structural or behavioral. Which of the following is an example of a behavioral adaptation?
A) shallow roots of cacti
B) long neck of a giraffe
C) migration of birds
D) webbed feet of ducks
Answer:
its c - the migration of birds
Explanation:
i did it on study island
How are solar flares different from solar prominences.
Answer:
What is the difference between a prominence and a solar flare? A prominence is a loop of cool incandescent gas that extends above the photosphere. A solar flare is an explosive release of energy that comes from the sun and causes magnetic ditrubances.
Explanation:
What holds the moon in place, orbiting around earth?
Answer:
Gravity
Explanation:
Mike stands on a scale in an elevator. If the elevator is accelerating upwards with 4.9 m/s2, the scale reading is ____ times Mike's weight.
Answer:
F - M a force exerted by scales on student
M a = M (9.8 + 4.9) m/s^2 upwards chosen as positive
a = 1.5 g net acceleration of student due to force of scales
W =M g weight of student (actual weight)
Wapp = M 1.5 * g apparent weight (on scales) of student
In an elevator which is accelerating upwards with 4.9 m/[tex]s^{-2}[/tex], Mike's weight will be 1.5 times the actual weight.
In the question, it is given that the lift is accelerating upwards with 4.9 m/[tex]s^{-2}[/tex] Let Mike's weight be "m", "g" is acceleration due to gravity and "a" be the upward accelerationThe upward acceleration of lift = 4.9 m/[tex]s^{-2}[/tex]As the lift is accelerating upwards, the apparent weight (R) = m (g+a)Apparent weight R = m*(9.8+4.9) NApparent weight R = m*(9.8+4.9)/9.8 KgfApparent weight R = m*1.5Hence, the apparent weight will be 1.5 times the real weight.
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