Using the kinematic equation ;
vf²=vi²+2ad just rearrange for d;
vf²-vi²=2ad;
(vf²-vi²)/2a=d
Now plug the numbers in.
vf=24.2
vi=0
a=9.81=g
(24.2²-0²)/(2*9.81)=29.8 m.
The effectiveness of an optical lens is attributed to:
diffraction
reflection
refraction
interference
refraction is the right answer
Answer: Refraction.
Explanation: The lenses are used to "transmit" the light that hits the lens in a certain way.
The phenomena in which the light penetrates a medium (where the medium, in this case, is the lens) is called diffraction.
Reflection would be more related to mirrors, difraction is the change of the velocity of the light waves when they are in different mediums, and interference refers to the interaction between two coherent waves (it can be destructive interference, where the waves cancel each other, or constructive interference, where the waves add to each other)
The waters of a lake will be most layered in which season
A. winter
B. spring
C. summer
D. fall
Answer:
B. Spring
Explanation:
The waters of a lake will be the most layered in the spring because of the melting of the ice (which is just frozen water) and the direct heat going into the lake causing the warm water to rise up and the colder water to move further down, which creates even more layers.
A worker pushes a crate horizontally across a warehouse floor with a force of 245 N at an angle of 55 degrees below the horizontal. How much of the worker’s force is not used to move the crate? (1 point)
Horizontal component of force is used to find out the work done
[tex]W = Fdcos\theta[/tex]
so we can say the work done as
[tex]W = (Fcos\theta)d[/tex]
so here the vertical component of force is not used to find out the work done
so here it would be
[tex]F_y = Fsin\theta[/tex]
[tex]F_y = 245sin55[/tex]
[tex]F_y = 200.7 N[/tex]
so 200.7 N is not used to find out work done
Two forces pull on an object at the same time. Their resultant force is least when the angle between the forces is _________. A. 0° B. 45° C. 90° D. 180°
Two forces pull on an object at the same time. Their resultant force is least when the angle between the forces is 180°.
Answer: Option D
Explanation:
When two forces are acting on an object, two possibilities are there.
(i) Forces acting on the same direction.
(ii) Forces acting o the opposite direction.
When two forces are acting on the same direction, their resultant force will be maximum, but when they are acting on the opposite direction, minimum resultant force will be the outcome (i.e) they are 180 degrees apart.
Which statement describes the process of subduction? Convection currents pull a plate into the mantle. One plate slides beneath another due to gravitational pull. Materials are transferred within Earth’s interior by density. Heat cycles in the mantle cause plates to constantly move.
The answer is B.one plate slides beneath another due to gravitational pull.
Answer:
Its B
Explanation:
took the test 2020
Seven-eighths of a sample of hydrogen-3 will have become a stable isotope after 36.9 years. What is the half-life of hydrogen-3? 12.3 years 18.5 years 32.3 years 36.9 years
Answer:
12.3 years
Explanation:
The equation of the radioactive decay can be written as follows:
[tex]\frac{N(t)}{N_0}=(\frac{1}{2})^{\frac{t}{\tau_{1/2}}}[/tex] (1)
where
N(t) is the amount of radioactive sample left at time t
N0 is the amount of radioactive sample at time t=0
t is the time passed
[tex]\tau_{1/2}[/tex] is the half-life of the isotope
The problem tells us that after t=36.9 y, the amount of sample which has become stable is 7/8. This means that 7/8 of the sample has already decayed, so the amount of radioactive sample left is
[tex]\frac{N(t)}{N_0}=1-\frac{7}{8}=\frac{1}{8}[/tex]
We can now re-arrange equation (1) by using this information and by substituting t=36.9 y we find:
[tex]\frac{t}{\tau_{1/2}}=log_{1/2} (\frac{N(t))}{N_0})\\\tau_{1/2}=\frac{t}{log_{1/2}(\frac{N(t)}{N_0})}=\frac{36.9 y}{log_{1/2}(1/8)}=\frac{36.9 y}{3}=12.3 y[/tex]
So, the answer is
12.3 years
Answer:
A. 12.3 years
Explanation:
What happens when oxygen reacts with sodium?
A. Electrons become delocalized among the atoms.
B. Electrons move form the sodium atoms to the oxygen atoms.
C. Electrons move from the oxygen atoms to the sodium atoms.
D. Electrons are shared between the sodium atoms and the oxygen atoms.
When oxygen reacts with sodium, the electrons move from the sodium atoms to the oxygen atoms which is denoted as option B.
What is Ionic bonding?This is referred to as electrovalent bonding and usually occurs between a metal and non metal.
The metal in this scenario is Sodium which loses electron to the non metal which is oxygen to become positively charged.
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At an auto race, a member of the pit crew stands beside the track. A car approaches him at 100 m/s and emits a sound at frequency 1100Hz. The air is still and the speed of sound is 340mls. What frequency will the pit crew member hear?
A.1560Hz
B.1420Hz
C.1640Hz
D.850Hz
Answer:
A. 1560 Hz
Explanation:
The Doppler effect occur when a source of a wave (like sound) is moving relative to an observer (or when the observer is moving relative to the source). When this happens, the apparent frequency of the sound as heard by the observer is shifted with respect to the real frequency, according to the formula:
[tex]f'=\frac{v}{v-v_s}f[/tex]
where
f' is the apparent frequency
v is the speed of the wave
vs is the velocity of the source relative to the observer (positive if the source is moving towards the observer, negative if it is moving away from the observer)
f is the real frequency of the wave
In this problem, we have the following data:
f = 1100 Hz is the original frequency of the sound
v = 340 m/s is the speed of the sound wave
[tex]v_s = 100 m/s[/tex] is the velocity of the car approaching the pit crew
Substituting these numbers into the formula, we can find the frequency heard by the pit crew:
[tex]f'=\frac{340 m/s}{340 m/s-100 m/s}(1100 Hz)=1558 Hz \sim 1560 Hz[/tex]
Answer: option A. 1560 Hz
Explanation:
Doppler effect is the phenomenon wherein the frequency of the source of the sound is different from what is received. This happens when either of the source or observer or both are relatively in motion.
In the given question, the observer is stationary and the source of sound is moving at the speed of [tex]v_s = 100 m/s[/tex] towards the observer. The frequency of the sound emitted is [tex]f_s = 1100 Hz[/tex]. The frequency heard by the pit crew member would be given by:
[tex]f_o = \frac{V}{V-v_s}f_s[/tex]
[tex]f_o = \frac{340 m/s}{340m/s - 100 m/s}\times 1100 Hz = 1558.3 Hz = 1560 Hz (approx)[/tex]
Thus, the frequency heard by the pit crew would be 1560 Hz. Correct option is A.
An object placed in water will float if the weight of the object is MORE THAN the buoyant force of the water.
True
False
False
If the object weighs more than the buoyant force then the object will sink.
This is because the buoyant force "pushes" the object upwards and the weight of the object "pushes" the object downwards. Since the force downwards is greater than the force upwards the item will sink, so this statement is False.
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If the current in a wire increases from 5 A to 10 A, what happens to its magnetic field? If the distance of a charged particle from a wire changes from 10 cm to 20 cm, what happens to its magnetic field? If the charge of a particle changes from 2 µC to –2µC, what happens to the force exerted on that particle?
1. The magnitude of the magnetic field doubles
Explanation: the intensity of the magnetic field produced by a current-carrying wire is given by:
[tex]I=\frac{\mu_0 I}{2 \pi r}[/tex]
where [tex]\mu_0[/tex] is the vacuum permeability, I is the current in the wire, r is the distance from the wire.
As we see from the formula, the intensity of the magnetic field is directly proportional to the current: if the current increases from 5 A to 10 A, it means it doubles, so the magnetic field doubles as well.
2. The magnitude of the magnetic field halves
Explanation: the intensity of the magnetic field produced by a current-carrying wire is given by:
[tex]I=\frac{\mu_0 I}{2 \pi r}[/tex]
We see that the magnitude of the magnetic field is inversely proportional to the distance from the wire (r). In this case, the distance of the particle is changed from 10 cm to 20 cm, so it is doubled: therefore, the magnitude of the field will become half of the initial value.
3. The force reverses direction
Explanation: the force exerted on a charged particle in a magnetic field is:
[tex]F=qvB sin \theta[/tex]
where q is the charge, v is the speed of the particle, B is the magnetic field intensity and [tex]\theta[/tex] the angle between the direction of v and B. If the charge of the particle is switched from 2 µC to –2µC, the magnitude of the force does not change (because the absolute value of q does not change), however the charge q gets a negative sign (-), so the sign of the force changes and gets a negative sign too, so the force reverses direction.
(a) When the current increases from 5 A to 10 A, the strength of the magnetic field increases.
(b) When the distance from the wire increases, the strength of the magnetic field decreases.
(c) When the sign of the charge changes and the magnitude is the same, the strength of the magnetic force will remain the same.
Magnetic field due to a distance from a wireThe magnetic field due to a distance from a wire is given as follows;
[tex]B = \frac{\mu_o I}{2\pi r}[/tex]
where;
I is current in the wirer is distance from the wireThus, when the current increases from 5 A to 10 A, the strength of the magnetic field increases.
Also, when the distance from the wire increases, the strength of the magnetic field decreases.
Magnetic force on a charged particleThe magnetic force on a charged particle moving in a magnetic field is given as;
F = qvB
where;
q is the magnitude of the chargeThe magnetic force considers the magnitude of the charge, thus when the sign of the charge changes and the magnitude is the same, the strength of the magnetic force will remain the same.
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Suppose you want to separate the leaves,acorns,and twigs from a pile of soil. Filtration and distillation are two processes of seperating mixtures. Explain which process you would use and why.
Filtration is the process we can use here as distillation is done mostly in liquids and we can use distillation here to seperate the substances from the soil.
Answer:
Filtration
Explanation:
Hi, to have in mind:
The filtration is a physical process used to separate two or more components due to their different size of particule (or unit).
The destilation is a chemical process used to separate two or more componets due to the difference between their boiling points (usually used with liquids).
Being that said, by filtration you can separate the leaves, acorns and twigs from the soil.
A ball is thrown vertically down from the edge of a cliff with a speed of 8 m/s, how high is the cliff, if it took 6 s for the ball to reach the ground?
The height of the cliff from which the ball was dropped from is 224.4m.
Given the data in the question;
Initial velocity of the ball; [tex]u = 8m/s[/tex]Time taken by the ball to reach the ground; [tex]t = 6s[/tex]Distance or Height of the cliff from which the ball was thrown from; [tex]s =\ ?[/tex]To get the height of the Cliff, we use the Second Equation of Motion:
[tex]s = ut + \frac{1}{2}at^2[/tex]
Where s is the distance or height, [tex]u[/tex] is the initial velocity, t is the time and a is the acceleration. Since the ball was thrown down from a certain height (cliff), its is now under the influence of gravity. acceleration due to gravity; [tex]g = 9.8m/s^2[/tex]
Hence, the equation becomes
[tex]s = ut + \frac{1}{2}gt^2[/tex]
We substitute the given values into the equation
[tex]s = ( 8m/s\ *\ 6s) + (\frac{1}{2}\ *\ 9.8m/s^2\ *\ (6s)^2)\\\\ s = ( 48m ) + (4.9m/s^2\ *\ 36s^2)\\\\ s = ( 48m ) + (4176.4m)\\\\ s = 224.4m[/tex]
Therefore, the height of the cliff from which the ball was dropped from is 224.4m
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Acceleration due to gravity is ( always / sometimes / never ) the same on the earth.
Sometimes, because acceleration due to gravity on Earth depends on how close you are to the Earth's center.
A friend says that tempature increases as altitude increases because you are moving closer to the sun. Is this true?
No, temperature change in the Earth's atmosphere is related to the distance from the sun, and temperature generally decreases altitude.
Answer:
This is true for some layers of the Earth's atmosphere.
Explanation:
As a counterexample: in the lowest layer of the atmosphere, with the highest density of gases, aka the Troposphere, the temperature decreases with increasing altitude. This relates to the sun heating up the surface some of which radiates back into the Troposphere.
However, the temperature increases with altitude in the Stratosphere (effect of ozone absorbing Sun rays), and it also increases with altitude in the Thermosphere (due to UV rays absorption).
The Mesosphere is another counterexample where the temperature decreases with increasing altitude.
experiment was performed on a 2-kg block. Forces of 5, 10 and 15 Newtons respectively were applied to the block for 5 seconds. Describe the difference in acceleration between the three trials. A) The final accelerations will all be the same. B) The final acceleration will triple between the first and third trial. C) The final acceleration will be cut by 1/3 from the first to third trial. D) The final acceleration will increase ni
Answer:
B) The final acceleration will triple between the first and third trial.
Explanation:
From the relationship (acceleration) = (force) / (mass) it follows that the acceleration is directly proportional to the force applied. During the second experiment the acceleration will double (as force doubles), and during the third it will be tripled compared to the first.
Materials have unique properties because each one is made up of different kinds of which particle?
A. Protons
B. Quarks
C. Electrons
D. Atoms
D. Atoms.
Explanation:
All the matter is made of elementary particles called "atoms".
Further, an atom is made of electrons, protons and neutrons. The electrons & protons are again made of the fundamental sub-particles, electrons (leptons) and the protons(quarks).
The classification of particles is shown in the figure attached
D. Atoms.
Because different kinds of atom have different number of protons, neutrons, and electrons.
What is the rms speed of nitrogen molecules contained in a 8.5 m3 volume at 3.5 atm if the total amount of nitrogen is 1900 mol ?
The root-mean-square (rms) speed of nitrogen molecules in a given volume and pressure can be calculated using the formula V_rms = sqrt(3kBT/m), where V_rms is the rms speed, T is the temperature in kelvin, k is the Boltzmann constant, and m is the mass of a nitrogen molecule. To solve this problem, we first need to find the temperature using the ideal gas law equation PV = nRT. Once we have the temperature, we can substitute it into the rms speed equation to find the final answer in m/s.
Explanation:The root-mean-square (rms) speed of nitrogen molecules in a given volume and pressure can be calculated using the formula:
Vrms = √( 3kBT/m ), where Vrms is the rms speed, T is the temperature in kelvin, k is the Boltzmann constant (1.38 × 10-23 J/K), and m is the mass of a nitrogen molecule.
In this case, we are given the volume (8.5 m3), pressure (3.5 atm), and total amount of nitrogen (1900 mol). To find the temperature, we need to use the ideal gas law equation: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant (0.0821 atm·L/mol·K), and T is the temperature.
Using the ideal gas law, we can solve for T:
T = PV/(nR)
Substituting the given values, T = (3.5 atm × 8.5 m3)/(1900 mol × 0.0821 atm·L/mol·K) = 16.573 K
Now we can calculate the rms speed:
Vrms = √( 3 × 1.38 × 10-23 J/K × 16.573 K / (28.0067 × 10-3 kg/mol) )
Calculating this expression will give us the rms speed of the nitrogen molecules in m/s.
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The rms speed of nitrogen molecules can be calculated using Boltzmann's constant, nitrogen's molar mass, and the given temperature in Kelvin. By substituting these values into the formula, we can compute the nitrogen molecules' speed.
Explanation:The rms speed (root mean square speed) of nitrogen molecules can be calculated using the formula:
Vrms = sqrt(3kT/m')
where k stands for Boltzmann's constant, T is the temperature in Kelvin, and m' represents the molar mass of nitrogen (N₂) molecule. According to the periodic table, the molar mass of nitrogen N₂ is 2(14.0067)x10-3 kg/mol. Plugging in the values and doing the calculation should give you the rms speed of the nitrogen molecules.
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Area of orifice is a. Due to ejection of water of density p at a constant speed, the equilibrium compression in spring is x. The speed of ejection of water is...
(Please answer ASAP !)
Thrust force due to ejection of water on the cart is counter balanced by spring force on the cart
so we can write
[tex]F_t = v \frac{dm}{dt}[/tex]
here we have
[tex]\frac{dm}{dt}[/tex] = rate of mass ejection
[tex]\frac{dm}{dt} = \rho a\frac{dx}{dt} = \rho a v[/tex]
now from above formula
[tex]F_t = \rho a v(v) = \rho av^2[/tex]
Now by force balance equation
[tex]F_t = F_s[/tex]
[tex]\rho a v^2 = kx[/tex]
by rearranging the terms now
[tex]v= \sqrt{\frac{kx}{\rho a}}[/tex]
Hot air balloon rises because a) molecules become lighter when heated b) molecules move faster and farther apart when heated c) molecules are less attracted by gravity when heated d) molecules become charged and repel each other when heated
Answer:
a. molecules become lighter when heated
Reason:
Here, a very simple scientific principle involved, that is hot air rises.When the air is heated, the density of air decreases, this causes the balloon to raise simply, because it is lighter than, an equal volume of cold air surrounds it. . Also, we know that the buoyancy is an upward force, that the air exerts a force, so that the hot air balloons fly in air.Hot air balloons rise because the heated air inside the balloon is less dense than the cool air outside. This difference in density creates a buoyant force that causes the balloon to rise. The increase in temperature causes the molecules in the gas to move faster and spread apart, further decreasing the density and increasing the buoyancy.
Explanation:Hot air balloons rise because the molecules in the heated air are less dense compared to the surrounding cool air. This decrease in density creates a buoyant force that causes the balloon to rise. As the temperature of the gas inside the balloon increases, the molecules move faster and farther apart, resulting in a decrease in density and an increase in buoyancy. The expansion of gases and the rapid motion of atoms and molecules in a gas also contribute to the balloon's ability to rise.
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Madison pushes with a 210-N horizontal force on a 24-kg crate of coffee resting on a warehouse floor. The force of friction on the crate is 74 N. What is the acceleration?
Answer:
5.7 m/s^2
Explanation:
First of all, we need to calculate the resultant force on the crate. We have:
- A force of +210 N in the positive direction
- The frictional force of -74 N in the opposite direction
So, the resultant force is
F = 210 N - 74 N= 136 N
So now we can apply Newton's second law to find the acceleration:
[tex]F=ma[/tex]
where m=24 kg is the mass of the crate. Re-arranging the equation, we get:
[tex]a=\frac{F}{m}=\frac{136 N}{24 kg}=5.7 m/s^2[/tex]
How do two isotopes of the same element different?
A. They have different numbers of protons.
B. They have different charges.
C. They have different atomic numbers.
D. They have different numbers of neutrons.
D. because Isotopes will have the same atomic number because they are the same element but have a different atomic mass because they contain a different number of neutrons.
Isotopes of the same element differ in the number of neutrons they contain, which leads to different atomic weights but doesn't change the chemical properties of the element.
Explanation:Isotopes are variations of a particular chemical element, which means they will always have the same number of protons and the same atomic number. However, isotopes of the same element differ in their number of neutrons. This can lead to different physical properties, such as mass, but the chemical properties remain largely unaffected because chemical behavior is determined by the number of electrons, which remains constant in isotopes of the same element. For example, Carbon-12 (12C) and Carbon-14 (14C), are both isotopes of Carbon where the number refers to the atomic weight, which changes due to the different numbers of neutrons.
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The law of reflection states that if the angle of incidence is 40 degrees, the angle of reflection is ___ degrees.
Answer
40 degrees
Explanation
When waves hit a surface they get reflected. The law of reflection states that the angle of incidence is equal to the angle of reflection. In this case, the law of reflection tells us that if the angle of incidence is 40 degrees, the angle of reflection is 40 degrees.
During a demonstration of the graviton always force on falling objects to her class , Sarah drops an 11lb bowling bowl from the top of the science building. Determine distance the ball has traveled after falling for 1.0 second, ignoring air restance and given the gravitational acceleration of 9.8m/sec^2
Answer:
4.9 meters
Explanation:
We know that an 11 lb bowling bowl was dropped.
So we can say that the initial speed of the bowling ball is zero ,
the time taken by the bag to free fall is given as t = 1.0 s; and
the acceleration of free fall is given as a = 9.8 m/s[tex]^2[/tex].
So we will use the following equation to find the distance after falling fo 1 sec:
[tex]d=v_i*t+\frac{1}{2} at^2[/tex]
Substituting the given values to get:
[tex]d=0+\frac{1}{2} * 9.8 * 1^2[/tex]
[tex]d=4.9[/tex]
Therefore, the bowling ball will cover a distance of 4.9 meters when released from the top of the building.
A 65 kg student climbs 7 m up a rope at a constant speed. If the students power to output is 300 w, how long does it take the student to climb the rope
g≈10 m/s²
F=G=mg=65*10=650 N
L=F*h=650*7=4550 J
P=L/t=>t=L/P=4550/300=15.16 s
In order of decreasing light-transmitting capabilities of materials, which is the correct sequence? A. Transparent -> translucent -> opaque B. Opaque -> transparent -> translucent C. Opaque -> translucent -> transparent D. Translucent -> transparent -> opaque
transparent --> translucent --> opaque
A. Is the correct answer
Answer:
A is the correct answer :)))
Explanation:
What is the name of the thin, dense membrane that covers the outer layer surface of the bone?
The answer is periosteum. Hope this helps!
The periosteum is the thin, dense membrane that covers the outer layer of bones, providing nourishment and playing a key role in bone growth, repair, and remodeling, excluding areas where bones form joints.
The thin, dense membrane that covers the outer layer surface of the bone is called the periosteum. This membrane is vitally important as it contains blood vessels, nerves, and lymphatic vessels that nourish the compact bone beneath it. Notably, the periosteum connects to the bone with strong collagen fibers known as Sharpey's fibers, which are integral in the attachment of tendons and ligaments. Although it covers most of the bone's surface, the periosteum does not cover the areas where bones form joints; these areas are protected by a different type of tissue. The function of the periosteum is not only protective; it also plays a crucial role in bone growth, repair, and remodeling due to its layer of bone-forming cells.
planet x has 4 times the mass of earth and a radius of half that of earth, how many times larger is the acceleration due to gravity on planet x then on earth?
4 times the mass of Earth . . . multiplies Earth gravity by 4
1/2 of Earth's radius . . . multiplies Earth's gravity by 4
both changes . . . multiplies Earth gravity by (4 x 4) = 16
The acceleration of gravity on the surface of Planet-X is 16 TIMES that on the Earth's surface ... about 6.3 times what it is on Jupiter.
You could not walk around on Planet-X, and it's pretty likely that whatever contraption you landed in could not take off again. You're stuck on Planet-X, living out the short remainder of your life just laying there like a heavy pancake and using all of your strength just trying to breathe. It won't be pretty.
A: If a net force greater than 0 N is applied to an electron and to a proton, which one will accelerate more? The mass of an electron is roughly 1 2000 th that of a proton. A) The electron will accelerate more than the proton. B) The proton will accelerate more than the electron. C) Both the proton and the electron will move at a constant speed. D) Both the proton and electron will accelerate by the same amount.
according to newton's second law , net force on an object is the product of mass of the object and the acceleration of the object. the formula is given as
F = ma where F = net force , m = mass and a = acceleration
so acceleration can be given as
a = F/m
for same net force , the acceleration depends on the mass of the object .
greater the mass , smaller will be the acceleration and vice versa.
Since the mass of electron is smaller as compared to the mass of proton, hence the electron will accelerate more as compared to proton.
A) The electron will accelerate more than the proton
A) the electron will accelerate more than the proton.
If the net force is greater than one, SOOO Newton’s second law of motion, an object will accelerate. The mass is inversely proportional to the acceleration. The lower the mass, the faster the acceleration,
hope this helps! :)
An atom has a charge of 1+. If the atoms nucleus caintains 23 protons, the atom must have how many electrons
Answer: 23 electrons.
Explanation: an atom have equal number of protons and electrons.
The intensity of a sound decreases by a factor of 4. As a result, the sound intensity level decreases by___.
A.4dB
B.6dB
C.8dB
d.16dB
Answer:
Option B is the correct answer.
Explanation:
We have expression for sound intensity level,
[tex]L=10log_{10}\frac{I}{I_0}[/tex], where I is the intensity.
Here new intensity is given by 4I.
So, increase in sound intensity level
[tex]\delta L=10log_{10}\frac{4I}{I_0}-10log_{10}\frac{I}{I_0}=10log_{10}\frac{4I}{I}=6dB[/tex]
So, option B is the correct answer.