Answer:
A longitudinal study is a research design that involves repeated observations of the same variables over short or long periods of time. It is often a type of observational study, although they can also be structured as longitudinal randomized experiments.
Explanation:
In Rutherford's model of the atom, the positive charge
A) occupies most of the space in the atom
B) is concentrated at the center of the atom
C) is distributed throughout the atom's volume
D) revolves about the nucleus in specific orbits
Answer:
the correct address is B
In Rutherford's model of the atom, the positive charge is concentrated at the center of the atom.
What is Rutherford's model?The model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun.
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The energy of an electromagnetic wave changes proportionally to which
other property?
O A Speed
O B. Shift
O c. Wavelength
O D. Frequency
Answer:
D. Frequency
Explanation:
The energy of an electromagnetic wave is proportional to frequency, mathematically it is expressed as;
E ∝ f
E = hf
where;
h is Planck's constant = 6.626 x 10⁻³⁴ Js
The equation above can also be expanded to;
[tex]E = hf = h \frac{c}{\lambda}[/tex]
where;
c is speed of light = 3 x 10⁸ m/s
λ is the wavelength of the electromagnetic wave
Since the speed of light is constant, we can conclude that the energy of the electromagnetic wave is directly proportional to its frequency and inversely proportional to its wavelength.
Therefore, the correct option for direct proportionality is FREQUENCY
What is the gravitational potential energy of a 3.0-kg rock that is 12.4 m above the ground?
Answer:
Explanation:
PE = mgh where m is mass, g is the pull of gravity, and h is the height to which the object can possibly fall.
PE = 3.0(-9.8)(-12.4) so
PE = 360 J, rounded to the correct number of sig figs.
The gravitational potential energy of the rock is 362.4 joules.
What is gravitational potential energy?The gravitational potential energy of an object is given by the formula:
PE = mgh
where PE is the potential energy, m is the mass of the object, g is the acceleration due to gravity (which is approximately 9.81 m/s^2 near the surface of the Earth), and h is the height of the object above a reference point.
In this case, the mass of the rock is 3.0 kg, the height above the ground is 12.4 m, and the acceleration due to gravity is 9.81 m/s^2. Substituting these values into the formula, we get:
PE = (3.0 kg) x (9.81 m/s^2) x (12.4 m) = 362.4 J
Therefore, the gravitational potential energy of the rock is 362.4 joules.
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1 Ten (10) ml aqueous solutions of drug A (10% w/v) and drug B (25% w/v) are stored in two identical test tubes under identical storage conditions at 37°C for 3 months. If both drugs degrade by first-order, which drug will retain the highest percentage of initial concentration?
Answer:
YOUR answer is given below:
Explanation:
Drug B will retain the highest percentage of initial concentration.
First order degradation means that both solution will degrade by same amount in same time because first order is directly proportional relationship between given both aqueous solution.
Given that Ten (10) ml aqueous solutions of drug A (10% w/v) and drug B (25% w/v) are stored in two identical test tubes.
Since, initially concentration of Drug B is more. Therefore, at all instant concentration of Drug will be highest.
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a bell rings at a frequency of 75hz on a warm 25 degree evening. calculate the...
a. speed of the sound wave at this temperature.
b. wavelength of the sound wave
Answer:
Explanation:
We need 2 different equations for this problem: first the velocity of sound equation, then the frequency of the sound equation.
The velocity of sound is found in:
v = 331.5 + .606T
We need to find that first in order to fill it into the frequency equation which is
[tex]f=\frac{v}{\lambda}[/tex] where v is the velocity we will find the part a, f is frequency and lambda is the wavelength. Starting with the velocity of the sound:
v = 331.5 + .606(25) and
v = 331.5 + 15 and rounding correctly using the rules for sig fig when adding:
v = 347 m/s
Filling that into the frequency equation:
[tex]75=\frac{347}{\lambda}[/tex] and
[tex]\lambda=\frac{347}{75}[/tex] so
[tex]\lambda=4.6m[/tex]
a string 2m long used to whirl a 200gm stone in horizontal circle at a speed of 2m/s . find the tension in the string
Answer:
Explanation:
First off, we need the mass in kg and it's in g so we have to convert it. Then we can do the problem. 200 g = .200 kg. Moving on.
The equation used to find the tension in the string is the same one we use to find the centripetal force, because the tension is what is upplying the centripetal force needed to keep the stone moving in a circular manner. The formula for that is
[tex]F_c=T=\frac{mv^2}{r}[/tex] where ma is the mass in kg, v is the velocity in m/s, and r is the radius of the circle about which the stone spins in meters.
Filling in:
[tex]T=\frac{(.200)(2)^2}{2}[/tex] which gives us
T = .4 N
which material has more specific heat?
Answer:
SO
Explanation:
SI
Answer:
Explanation:
dynamic equilibrium
what are scalar quantities and list their examples
Explanation:
these are quantities that have magnitude but no direction
Examples include : speed, mass, volume, density, everything, time
Which one of the following is an example of a solution?
a. Sand particles in water
b. Orange Squash
c. Vinegar
d. Paint
Answer:
it is maybe A but i'm not 100% sure
Explanation:
its the only one that is mixed
As Courtney switches on the TV set to watch her favorite cartoon, the electron beam in the TV tube is steered across the screen by the field between two charged plates. If the electron experiences a force of 3.0 * 10^6 N, how large is the field between the deflection plates?
Answer:
Explanation:
Force= (q1q2)/(4/\Ęr2)
3×10^6= (1.602×10^-19)^2/(r^2)
r^2=(2.27×10^-33)/(3×10^6)
r^2=8.55×10^-45
r= 9.25×10^-23
Bones are composed of three main components, what are they? (Choose all that apply)
Answer:
funny bone and compact bone
Explanation:
your funny bone only reacts if you hit it against something the compact bone is the heaviest and strongest bone in your body and the bone marrow is soft sponge like tissue in the center if most bones that produces white and red blood cells
a man runs 1200m on a straight line in 4 min . find his velocity.
Answer:
5m/sec^2
Explanation:
Distance=1200m
Time=4 min
1=60sec
4=4 x 60
=240sec
Velocity=Distance/Time
Velocity=1200/240
Velocity=5m/sec^2
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pleaseeeeeee helppppp this is mah last question... thank u (. ^ ᴗ ^. )
Answer:
44.1 m
Explanation:
Consider the displacement being x:
x = (g•t²)/2
x = (9.8•3²)/2
x = (9.8•9)/2
x = 88.2/2
x = 44.1 m
Answer:
44.1 mExplanation:
that's the correct answer
Multiplying a vector with another vector results in what type of answer.
A) a direction
B) a vector
C) either a vector or a scalar
D) a scalar
multiplication of two vectors yields a vector oroduy
what is electricity?write any two defects of a simple cell.
Answer:
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations.
help please!!
From the following images shown, classify the interactions that occur and say between which bodies, according to the following criteria:
a) Contact forces
b) Non-contact forces
Answer:
B= 4 A=5
Explanation:
Waves break on a beach due to:
reducing depth of water near beach
increasing wavelength near beach
turbulence near the shoreline
Answer:
increasing wavelength near beach
Explanation:
When wavelength increases, frequency of these waves decreases and the waves suddenly stop.
This is also called damped oscillation.
10 points
Calculate the force of attraction between the moon and the earth, if their masses and distance apart are 10^22Kg, 10^24kg and 6.4x10^6m. Take g = 6.67x10^-11Nm^2Kg^-2
a) 0.63x10^24N
b) 1.63x10^22N
c) 2.63x10^20N
d) 3.63x10^18N
Answer:
Explanation:
You didn't fill in the proper masses which is why you never got an answer to this. But that's ok...I got you. I happen to know what they are! We will use the universal law of gravitation and the gravitational constant to solve this.
[tex]F_g=\frac{Gm_1m_2}{r^2}[/tex] and filling in:
[tex]F_g=\frac{(6.67*10^{-11})(5.98*10^{24})(7.36*10^{22})}{(3.84*10^8)^2}[/tex] The denominator is the radius of the earth plus the radius of the moon plus the distance between their surfaces, just FYI.
That gives us that
[tex]F_g=1.99*10^{20}N[/tex] Not sure what your choices entail, but I'd have to say, taking into consideration that maybe your problem didn't figure in the distance between the surfaces, you'd be at choice B.
Vector B has components Bx = 6.18 and By = 4.43. Find the magnitude and direction counter clockwise from the positive x-axis.
Answer:
Explanation:
The formula for the magnitude of this resultant vector, which is in Q1, btw, is:
[tex]B_{mag}=\sqrt{6.18^2+4.43^2}[/tex] which gives us, to 3 sig fig's:
7.60 m. Since the resultant vector is in Q1, we don't need to add anything to the angle once we find it to 3 sig fig:
[tex]tan^{-1}(\frac{4.43}{6.18})[/tex] gives us an angle of 35.6 degrees
The velocity of sound in a medium increases with increasing
a. distance
b. amplitude
c. temperature
d. time
c- temperature
The speed of sound increases with increasing temperature .
goodie morning
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what is nitric acid?
Answer:
Nitric acid, also known as aqua fortis and spirit of niter, is a highly corrosive mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to decomposition into oxides of nitrogen and water. Most commercially available nitric acid has a concentration of 68% in water.
Explanation:
Good morning...
Nitric acid production is mainly driven by fertilizer industry. Nitric acid is used in the production of ammonium nitrate and calcium ammonium nitrate which find applications as fertilizers.
How is an ammeter connected in a circuit to measure current flowing through it?
Answer:
It is connected in series with the circuit
Explanation:
This is because to measure the current in the circuit, the current in the circuit has to flow through the ammeter. As such, the ammeter must be connected in series with the circuit so as to measure the current flowing through the circuit.
So, to measure the current flowing through a circuit with an ammeter, the ammeter must be connected in series with the circuit.
In April 1974, Steve Prefontaine completed a 10.0 km race in a time of 27 min , 43.6 s . Suppose "Pre" was at the 7.71 km mark at a time of 25.0 min . If he accelerated for 60 s and then maintained his increased speed for the remainder of the race, calculate his acceleration over the 60 s interval. Assume his instantaneous speed at the 7.71 km mark was the same as his overall average speed up to that time.
Answer:
0.18 m/s²
Explanation:
The total time taken to cover a 10 km race is 27 min, 43.6 seconds.
At 25 min, Pre was at 7.71 km mark. Therefore the average speed = 7.71 km / 25 min = 7710 m / (25 * 60) s = 5.14 m/s
The distance remaining = 10 km - 7.71 km = 2.29 km = 2290 m
The remaining time = 27 min, 43.6 seconds - 25 min = 2 min 43.6 second = 163.6 seconds
She accelerates for 60 seconds, therefore the distance covered (S) during the acceleration (a) is:
S₁ = 5.14(60) + 0.5a(60)² = 308.4 + 1800a
She maintains the speed for the remaining distance (S₂). The remaining time = 163.6 seconds - 60 seconds = 103.6 seconds. The final speed after the acceleration = (5.14 + 60a) m/s
S₂ = (5.14 + 60a)* 103.6 = 532.5 + 6216a
S₁ + S₂ = 2290 m
(308.4 + 1800a) + (532.5 + 6216a) = 2290
8016a + 840.9 = 2290
8016a = 1449.1
a = 0.18 m/s²
the use of thermostat in a gas cooker is to
Explanation:
An oven thermostat regulates the temperature inside an oven. The thermostat's temperature-sensitive probe measures the oven's warmth, switching the heat on and off as necessary to maintain the correct temperature.
how does energy change ? explain with example . how does bulb generate ? write with it's part.
Answer:
According to the law of conservation of energy, energy is neither created nor destroyed but changes from one form to another
The energy in the light bulb comes from the movement of electrons through the resistance of the coil of the bulb, therefore, the energy in the bulb is changed from electric energy to heat and light energy as follows;
The friction between the moving electrons and the resistive filament of the light bulb results in the slowing down of the rapidly moving electrons
The part change in the (kinetic) energy of the electrons moving through the filament of the bulb as they slow down is observed as sensible heat which causes the bulb to be hot
Another part of the change in energy is given seen as the light given off by the bulb filament in an incandescent bulb as the filament becomes very hot from the movement of the electrons which causes the bulb to glow (produce light), due to the incandescent characteristics of the filament
Explanation:
A cyclist is taking part in the Tour de France, which is a bicycle race that takes place every year.
a Two forces acting on the cyclist are weight and reaction. Name two other forces acting on him
as he cycles along.
the volume of vessel is 6 litres. convert it into ml
A rope horizontally pulls a massive object lying on a surface with friction with a constant
velocity. What describes the force on the rope?
Answer:
Equal to the frictional force
Explanation:
Question; The options given with regards to a similar question posted online are;
A. Equal (equivalent) to the frictional force
B. Larger than the frictional force
C. Equal to the object's weight
D. More than the object's weight
Explanation
According to Newton's first law of motion, every object shall remain at rest or continue moving with uniform (constant speed) motion unless there is a net force acting on the object
Given that the velocity of the massive block, lying on the surface that has friction, being pulled by the rope = Constant
Therefore;
The net force acting on the moving block while being pulled by the rope = 0
From which we have;
The pulling force = The resistive force
Where;
The pulling force = The (pulling) force (applied) on the rope
The resistive force = The frictional force of the surface which tends to prevent the motion of the block
Therefore, given that the net force acting on the block = 0
The force on the rope = The frictional force (of the surface)
The correct option is option A. Equal to the frictional force.
what is parking orbit?
Answer:
A temporary orbit in which a spacecraft awaits the next phase of its mission .
(b) During one day, 250 kg of water is pumped through
the solar panel. The température of this
water rises from 16°C to 38°C.
The water absorbs 25% of the energy incident on the solar panel. The
specific heat capacity
of water is 4200J/(kg °C).
Calculate the energy incident on the solar panel during that day.
Please explain how to find the incident energy
Answer: The energy incident on the solar panel during that day is [tex]9.24 \times 10^{7} J[/tex].
Explanation:
Given: Mass = 250 kg
Initial temperature = [tex]16^{o}C[/tex]
Final temperature = [tex]38^{o}C[/tex]
Specific heat capacity = 4200 [tex]J/kg^{o}C[/tex]
Formula used to calculate the energy is as follows.
[tex]q = m \times C \times (T_{2} - T_{1})[/tex]
where,
q = heat energy
m = mass of substance
C = specific heat capacity
[tex]T_{1}[/tex] = initial temperature
[tex]T_{2}[/tex] = final temperature
Substitute the values into above formula as follows.
[tex]q = 250 kg \times 4200 J/kg^{o}C \times (38 - 16)^{o}C\\= 250 kg \times 4200 J/kg^{o}C \times 22^{o}C[/tex]
As it is given that water absorbs 25% of the energy incident on the solar panel. Hence, energy incident on the solar panel can be calculated as follows.
[tex]\frac{25}{100} \times q = 250 kg \times 4200 J/kg^{o}C \times 22^{o}C\\q = 9.24 \times 10^{7} J[/tex]
Thus, we can conclude that the energy incident on the solar panel during that day is [tex]9.24 \times 10^{7} J[/tex].
