Answer:
100,000 / 800,000 = 1 / 8 amount of sample after 12 hours
(1/2)^n = 1 / 8 after n half-lives 1/8 of sample will be left
n = 3
(D) is the correct answer - 1/2 half-life = 4 hours
A laser emits a narrow beam of light. The radius of the beam is 1.5 mm, and the power is 1.9 mW. What is the intensity of the laser beam?
Answer: 268.80 W/m^2
Explanation:
Intensity = Power/Area
first convert radius to meters
1.5mm= 1.5x10^-3m
area= pi (1.5x10^-3)^2
= 7.069m^2
convert power to W
1.9mW= 1.9x10^-3W
plug into intensity formula
(1.9x10^-3)/(7.069) = 268.80 W/m^2
2. Following a strength training plan, someone who increases lean muscle mass by .5 pounds per month will achieve a weight gain of ______
a) 5 pounds in two months.
b) pound in one month.
c) 2 pounds in four months
Answer:
C
Explanation:
.5 lb/month * 4 month = 2 lbs
A net force of 15N is applied to a cart with a mass of 5kg. What is the
acceleration of the cart?
Answer:
3 m/s^2
Explanation:
Simply F = ma
15 = 5 a
a = 3 m/s^2
Look at the diagram. Both cars start from the same point. Which describes the motion shown?
A:One car travels south at 4 m/s. The other car travels east at 2 m/s.
B:One car travels north at 4 m/s. The other car travels west at 2 m/s.
C;One car travels north at 2 m/s. The other car travels east at 4 m/s.
D: One car travels south at 4 m/s. The other car travels west at 2 m/s. 7 of 10
The original photo wouldn't load...
Answer: The answer is C.
Explanation: C is the correct answer. The magnitude of the vector increases with the length of the line. Consider a compass when it comes to direction.
Superkid, finally fed up with Superbully's obnoxious behaviour, hurls a 1.35 kg stone at him at 0.501 of the speed of light. How much kinetic energy do Superkid's super arm muscles give the stone
Answer:
See below
Explanation:
A lot !
KE = 1/2 m v^2
= 1/2 * 1.35 * ( .501 * 3 * 10^8)^2 =
1.5248 x 10^16 j
kinetic energy do Superkid's super arm muscles give the stone is 62.6 × 10⁶ J.
What is kinetic energy ?Kinetic energy is the energy associated with a motion of a body. When a body is in motion having mass m then it has kinetic energy. Kinetic energy is denoted by K or T. it is expressed in joules. Kinetic energy is given by,
K = 1/2 mv²
Hence an object having zero mass or zero velocity have zero kinetic energy.
In this problem the stone is moving with velocity which is comparable with the speed of light, hence we have to find relativistic kinetic energy.
The relativistic kinetic energy is given by,
[tex]K = m_{0} c^2(\frac{1}{\sqrt{1-\frac{v^2}{c^2}} } -1)[/tex]
putting all the values in the equation
[tex]K = 1.35*3*10^8(\frac{1}{\sqrt{1-\frac{(0.5c)^2}{c^2} } }-1 )[/tex]
K = 62.6 × 10⁶ J
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A boy swings a 30 g fishing sinker around his head attached to his fishing line. The radius ofthe circular motion of the sinker is 65 cm. The sinker does 2 revolutions per second.
(a) What is the period of rotation of the sinker?
(b) What is the tangential velocity of the sinker?
(c) Calculate the acceleration of the sinker.
Explanation:
a) Peroid = 1/frequency
F = 2 rev. per second = 2Hz
period = 1/2 = 0.5s
b) Tangential velocity(Vt) = ωr, where ω is thr angular velocity(2 * Pi(3.142) * f(frequency)) and r is the radius
Therefore; Vt = 2 * 3.142 * 2 * 0.65(65/100)
= 8.1692
= 8.2m/s
c) a = (V^2)/r where V is the velocity and r is the radius
a = (8.2^2)/0.65
a = 103m/s^2
A 30kg bullet strikes a tree trunk of diameter 40cm at 200ms and leaves it from the opposite side at 100ms find the kinetic energy of the bullet just before it strikes the tree
Answer:
Before it strikes the tree:
KE = 1/2 m v^2 = 1/2 * 30 kg * (200 m/s)^2
This KE would be 6.0E5 Joules
30 kg would about 66 lbs - obviously too heavy
You might consider 30 mg = .03 kg (still quite heavy)
KE = 1/2 * .03 kg * 40000 m.s^2 = 600 J more realistic
calculate the kinetic energy of a 71 kg man running at 5 m/s
Answer:
887.5 J
Explanation:
Kinetic energy is the energy gained by a body due to its motion.
Its formula is :-
KE = [tex]\frac{1}{2} mv^{2}[/tex]
m = massv = velocityValues we are given :
m = 71 kgv = 5 m/sSubstituting :
KE = 1/2 x 71 x 5²KE = 35.5 x 25KE = 887.5 JWhile looking through a telescope, an astronomer views an object that is moving and appears to have a tail. The astronomer states that the tail is caused by evaporation. What is the astronomer most likely observing?.
Answer:
A comet
Explanation:
A comet is composed of mostly ice. As it passes close to the sun, it warms up and begins to release gases, the gases seem longer and they look like a tail. Because the ice gets warmer close to the sun and because it's icy, it changes from ice to liquid and finally vapour. hence evaporaction.
A tow truck pulls a 3500 kg mazda car out of the mud. The car is moved 20 M in 4 seconds by the truck. What is the work done by the tow truck
Answer:
W = F * S one does not know the work performed because one does not know what force produced the resulting work. Neither can one calculate the power required because P = W / t (work / time)
One only knows the distance and the time but not the force required.
Plants cause weathering, too. a seed that falls into a crack in a rock may grow there. growing roots may push on and enlarge the crack, what is this process called question 3 options: chemical weathering mechanical weathering root-pry pedalfer
The process which involves plants to cause weathering to a seed that falls into a crack in a rock therefore, breaking apart the rock is called Mechanical weathering.
Mechanical weatheringThis is defined as the set of weathering processes that break apart rocks into particles (sediment) through physical processes. The most common form of mechanical weathering is the freeze-thaw cycle. Water seeps into holes and cracks in rocks then the water freezes and expands, therefore making the holes larger eventually making the rock split apart.
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Answer:
root-pry
Explanation:
i took the test
Which two characteristics might a model have if it is a three-dimensional model of magnetic force made by using a magnet and magnetic field lines? A. Some field lines have arrows that point in different directions. B. Arrows on the field lines point from the magnet's north pole to its south pole. C. The field lines are closest together in and near the magnet D. The field lines cross paths as they go from one pole of the magnet to the other.
Answer:
B C I suppose , though A is correct too
Explanation:
The arrows on the magnetic field lines point from the magnet's north pole to its south pole. The field lines are closest together in and near the magnet. Thus, the correct options are B and C.
What is Magnetic force?Magnetic force is the force of the electrically charged particles which are in motion, such as attraction, or repulsion results from their activity. It is the fundamental force behind the phenomena like how electric motors operate and magnets are drawn to metals.
Usually, when we draw magnetic field lines, we start to draw outwardly from the North pole to the South Pole. This same direction is prevalent on the Earth due to the fact that the Earth functions as a giant magnet. Thus, the model describes that the magnetic field lines will spread out of the north end of the magnet to the south end. The magnetic field lines are closest in and near the magnet.
Therefore, the correct options are B and C.
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When an old information system in shut down and a new system starts up right after the shut down, we call this a __________ inforomation system conversion. phased parallel plunge pilot
Parallel information system is when an old information system in shut down and a new system starts up right after the shut down.
What is an information system?An information system is a system in which information are passed or transmitted from one end to another especially from senders to receivers to achieve a particular goal.
Therefore, Parallel information system is when an old information system in shut down and a new system starts up right after the shut down.
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When studying the photoelectric effect, which parameters did scientists think were relevant for electrons to be released or not in both the wave and particle models?
A. intensity only for both models
B. frequency and intensity for the particle model; frequency only for the wave model
C. frequency only for both models
D. frequency and intensity for the wave model; frequency only for the particle model
I marked it as B, but I am not certain.
Answer:
D.
Explanation:
The answer should be D. frequency and intensity for the wave model; frequency only for the particle model.
I hope it helps! Have a great day!
Anygays-
The parameter will be frequency and intensity for the wave model and the frequency only for the particle model.
What is the photoelectric effect?When a medium receives electromagnetic radiation, electrostatically charged particles are emitted from or inside it.
The emission of ions from a steel plate when light falls on it is a common definition of the effect. The substance could be a solid, liquid, or gas; and the released particles could be protons or electrons.
The above effect is the photoelectric effect. Frequency and intensity for the wave model; frequency only for the particle model.
Hence option D is correct.
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Distinguish between infrasonic and ultrasonic sound waves.
How we could distinguish them is that the infrasonic sounds are the lower limit of human hearing while ultrasonic sound is above human hearing. The sound of frequency more than 20,000Hz are called ultrasonics while the frequency less than 20Hz are called infrasonics.
Explanation:
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A primary difference between momentum and kinetic energy is momenta can cancel; kinetic energy cannot. kinetic energy can cancel; momenta cannot. either of the above depending on circumstances none of the above
The primary difference between momentum and kinetic energy is kinetic energy can cancel momentum.
What is kinetic energy?The kinetic energy of an object is the energy possessed by the object due to its motion.
KE = ¹/₂mv²
where;
m is mass of the objectv is the velocityWhat is momentum of object?Momentum of an object is the measure of the rate at which a mass is moving.
P = mv
K.E = ¹/₂(P)v
Thus, the primary difference between momentum and kinetic energy is kinetic energy can cancel momentum.
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Most stars in the Milky Way's halo are _________. blue or white in color very young very old found inside molecular clouds
Answer:
Most stars in the Milky Way's halo are very old
very oldThere is no recycling of gas in the halo, so halo stars are quite old.
The requried, "Most stars in the Milky Way's halo are very old."
What is milk way's halo?The Milky Way halo is a large, spherical region surrounding the disk of the galaxy, and it is believed to be composed primarily of ancient stars that formed early in the history of the galaxy.
Here,
These stars are typically metal-poor, which means they have lower abundances of elements heavier than hydrogen and helium compared to stars in the disk. They are also old, with estimated ages of several billion years or more.
The halo stars are believed to have formed in small, isolated systems that were later accreted by the Milky Way. They are widely dispersed and do not form dense concentrations like those found in the disk or in globular clusters.
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For pea plants, T represents a dominant allele for tall pea plants and t is the recessive allele for short pea plants. If two plants with the Tt genotype are crossed, what is the probability that offspring will exhibit the dominant trait?
Answer:
75%(TT,Tt,tt) Hope that helps
Which two energy sources can help a star maintain its internal thermal pressure?.
A (1.03x10^2)-mA current is used to charge up a parallel plate capacitor. A large square piece of paper is placed between the plates and parallel to them so it sticks out on all sides. What is the value of the integral ∮B⃗ .ds⃗ around the perimeter of the paper? Express your result in T.m with three significant figures.
Since a 1.03 × 10² mA current is used to charge up the parallel plate capacitor and a large square piece of paper is placed between the plates and parallel to them so it sticks out on all sides, the value of ∫B.ds around the perimeter of the paper is 1.29 × 10⁻⁷ Tm
Ampere's LawThis shows the relationship between the magnetic field, B, the path of integration, ds and the current enclosed by the magnetic field, i.
Ampere's law is given mathematically as
∫B.ds = μ₀i where
B = magnetic field, ds = arc length of path of integration, μ₀ = permeability of free space = 4π × 10⁻⁷ Tm/A and i = current enclosed by the path of integration, ds.Given that for the large square piece of paper, the current used to charge the capacitor is
i = 1.03 × 10² mA = 1.03 × 10² × 10⁻³ A = 1.03 × 10⁻¹ A and ds = path length around the perimeter of the paperThe value of ∫B.ds around the perimeter of the paperSince ∫B.ds = μ₀i
Substituting the values of the variables into the equation, we have
∫B.ds = μ₀i
∫B.ds = 4π × 10⁻⁷ Tm/A × 1.03 × 10⁻¹ A
∫B.ds = 4.12π × 10⁻⁸ Tm
∫B.ds = 12.94 × 10⁻⁸ Tm
∫B.ds = 1.294 × 10⁻⁷ Tm
∫B.ds ≅ 1.29 × 10⁻⁷ Tm
So, the value of ∫B.ds around the perimeter of the paper is 1.29 × 10⁻⁷ Tm
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What type of particle carries an electric current through a wire? Voltage is another name for the __________ difference. What word completes the sentence?
Answer:
electric potentialbrainless plsss
Which nasa spacecraft is studying jupiter and its moons?.
Answer:
Juno
Explanation:
The NASA spacecraft Juno (2016) is the one that was studying Jupiter more in detail.
I hope it helps! Have a great day!
Anygays-
If 100 kg person weighed 400 N on the planet Zorg,
what is the acceleration due to gravity on Zorg?
Answer:
4 m/s²
Explanation:
Formula
Weight = Mass x Gravity due to accelerationSolving :
400 N = 100 kg x gg = 400/100g = 4 m/s²Answer:
Explanation:
accleration = Force /mass
a = 400 / 100
a = 4 m/s^2
Force f acts between two charges, q1 and q2, separated by a distance d. if q1 is increased to twice its original value and the distance between the charges is also doubled, what is the new force acting between the charges in terms of f? one quarterf one halff f 2f
The new force acting between the charges in terms of f given the data from the question is half f
Coulomb's law equationF = Kq₁q₂ / r²
Where
F is the force of attraction K is the electrical constant q₁ and q₂ are two point charges r is the distance apart How to determine the initial force Charge 1 = q₁Charge 2 = q₂ Electric constant (K) = 9×10⁹ Nm²/C²Distance apart (r) = dInitial force (F₁) = f =?F = Kq₁q₂ / r²
F₁ = f = Kq₁q₂ / d²
How to determine the new force Charge 1 = 2q₁Charge 2 = q₂ Electric constant (K) = 9×10⁹ Nm²/C²Distance apart (r) = 2dNew force (F₂) =?F = Kq₁q₂ / r²
F₂ = K2q₁q₂ / (2d²
F₂ = 2Kq₁q₂ / 4d²
F₂ = Kq₁q₂ / 2d²
F₂ = ½(Kq₁q₂ / d²)
But
f = Kq₁q₂ / d²
Therefore
F₂ = ½f = half f
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Answer:
C or 1/2
Explanation:
The density of water is 1.0 gram per milliliter at 4 degrees Celsius.
Shelby drops a spoonful of sugar into water at this temperature and it
sinks to the bottom of the container. Compare the densities of the sugar
and water and explain how this affects the position of the sugar in the
liquid water.
Sugar molecules present at the bottom of solution due to more mass.
Which is more denser water or sugar?Table sugar is more dense than water due to the presence of more mass of sugar molecule as compared to water. We know that denser objects has more mass so that's why sugar molecules present at the bottom of solution due to more mass.
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A sound wave has a wavelength of 1.32 m and travels at a speed of
350 m/s. What is the frequency of this sound wave?
Answer:
0.00377143
Explanation:
You would have to divide to get the frequency.
1.32/350 = 0.00377143
I apologize if it is incorrect-
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Anygays-
Which statement describes the law of conservation of energy
Answer:
law of action and riactiond
A 400g mass object at rest is acted on by a 200 N net force for 12 seconds. What is it’s final velocity?
The answer is supposed to be 6000 m/s but I’m not sure how…
Explanation:
do we can say that the first step is finding the acceleration of the object. We do so by saying F = ma
so a = F/m
a = 500 m/s^2
we now have the time, acceleration and initial velocity.
so we can find the final velocity by using one of newtons equations which is: vf = vi + at
so:
vf = 0 + 500 × 12
vf = 6000
note that our initial velocity was zero since the object was initially at rest.
if you still have any doubt dont hesitate to ask for further help.
A car travels from City A to City B to the north. It takes 4 hours, and the road mileage is 200 miles. The map shows that
the cities are only 80 miles apart (straight-line distance).
Answer:
The average speed would be the 200 miles/4 hours.
The average velocity would be the net displacement to the north at 80 miles/4 hrs = mph
Explanation:
A scuba diver uses his waterproof flashlight to shine a beam of light so that it strikes the surface of the water at an angle of incidence . Use Snell’s law to find the angle of incidence that would give an angle of refraction for the refracted ray to be directed right along the surface, and show that is the same as the critical angle for total internal reflection.
Answer:
the light speed up and change it directtions
