What is the critical angle for glass when the refractive index is 1.45
Answer:43.6°
Explanation:
Refractive index=n=1.45
Critical angle=c
n=1/sinc
1.45=1/sinc
Cross multiply
1.45sinc=1
Divide both sides by 1.45
(1.45sinc)/1.45=1/1.45
sinc=0.6897
c=sin(inverse)(0.6897)
c=43.6°
Critical angle is 43.6°
A researcher is investigating the effect of Paxil in treating PTSD in veterans. He does a search throughout the US and gets 1000 veterans to receive the Paxil; 1000 veterans to get a placebo sugar-pill; and 1000 veterans to take a daily vitamin In this study ___ is the population and ___ is the sample.
Answer:
The total number of people in the US is the population while the 3000 people selected for the study is the sample.
Explanation:
In the study according to the illustration, the population of study is the total number of people in the US while the sample is the number of people selected out of the population for the study which is 3000.
In a research, a population refers to the total number of individuals present in an area at a specific time where researchers wish to conduct their study.
A sample, on the other hand, refers to a portion of a population of interest during a research, that is selected via a suitable sampling procedure to represent the entire population.
It is most often virtually impossible, time, and resource consuming to study the entire population during a research, especially for a large population. Hence, sampling represents a faster and more economic way of studying populations although this leaves room for different margins of errors.
How do coal deposits found in the U.S. and Serbia help prove the theory of continental drift?
Answer:
Wegner's hypothesis met with wide skepticism, but found support and development in ... theory because Wegener could not satisfactorily explain how the continents moved.
Explanation:
Some of his theory was proven wrong, but he was still correct about his hypothesis. The fossils were part of proof for the theory because some of the fossils were found on shore line. And, some of those animals couldn't swim. So, this is proof that some animals lived on the land. And over time the land drifted apart.
Oliver builds a circuit connecting a light bulb to a battery with wires, leaving a gap in one of the wires. He places several objects across the gap to close the loop. He wants to see which objects allow electricity to flow and turn on the light bulb. Why do some materials allow electricity to flow through while others do not?
A. Electricity will flow if the atoms in the material are bound tightly to each other.
B. Electricity will flow if the atoms in the material are bound loosely to each other.
C. Electricity will flow if the electrons are bound tightly to their atoms in the material.
D. Electricity will flow if the electrons are bound loosely to their atoms in the material.
Answer:
D. Electricity will flow if the electrons are bound loosely to their atoms in the material.
Explanation:
The continuous flow of charges is known as electricity (current). The flow of these charges are due to free or mobile electron within the atoms of the conductors. The materials which will allow current to pass through them, must have free or mobile electrons which are loosely bound to their atoms.
Thus, the correction for this question is "D"
D. Electricity will flow if the electrons are bound loosely to their atoms in the material.
In which sound wave application are sound waves absorbed?
Answer: ultrasonic cleaners
Explanation:
To solve this we must be knowing each and every concept related to sound wave. Therefore, in ultrasonic cleaners, sound waves are absorbed.
What is sound wave?A sound is a type of energy or a vibration that moves through a material such as air or water. Sound may pass through such a gaseous medium as well. It is anything that is audible. The velocity of sound varies depending on the medium.
A wave is a medium that transmits energy from one location to another. Waves are classified into three types: transverse waves, longitudinal waves, or surface waves.
Transverse waves transport the material back and forth in a right angle towards the energy movement. Longitudinal waves transmit energy through compressing then expanding the medium, allowing the energy to travel ahead. In ultrasonic cleaners, sound waves are absorbed.
Therefore, in ultrasonic cleaners, sound waves are absorbed.
To know more about sound wave, here:
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Chuck's car is moving at 65.0m/s when he suddenly accelerates his car at 15.0m/s2 for 3.00s. How far did Chuck, and his car, travel while he was accelerating?
Answer:
x = 265.5 m
Explanation:
To find the distance traveled by the car you first use the following formula:
[tex]v=v_o+at[/tex] (1)
vo: initial velocity = 65.0m/s
a: acceleration = 15.0m/s^2
t: time = 3.00 s
you replace the values of vo, t and a in the equation (1) in order to calculate the final velocity v:
[tex]v=65.0m/s+15.0m/s^2(3.00s)[/tex] = 110 m/s
Next, you use the following formula:
[tex]v^2=v_o^2+2ax[/tex]
x: distance traveled
You do x the subject of the formula and replace the values of vo, v and a:
[tex]x=\frac{v^2-v_o^2}{2a}\\\\x=\frac{(110m/s)^2-(65.0m/s)^2}{2(15.0m/s^2)}=262.5\ m[/tex]
hence, the distance traveled by the car is 265.5 m
You are alertly driving a car at 40 MPH (18 m/s). You come around a
bend and see a tree that has fallen across the road 50 meters away. Will
you be able to stop before you hit the tree:
a. on a dry road? Show your evidence.
b. on a wet road? Show your evidence.
Answer: A because yoir tires will grip the ground other than the wet road you will slide and go of in the ditch or go into the tree ...hope this helps
Explanation:
Una barra de longitud de 2 m está cargada uniformemente y tiene una carga total de 5nC. Busqué su potencial eléctrico (relativo acero en el infinito) en un punto que se encuentra a lo largo del eje de la barra y está a 3m del centro de la barra?
Answer:
11.44J/C
Explanation:
To find the electric potential for a point at 3m from one extreme of the bar you use the formula for the electric potential:
[tex]V=\int k\frac{dq}{r}=\int k\frac{dq}{x+3}[/tex]
Where r = x+3 represent the 3m distance of the charge to a point x in the bar.
dq: differential of charge = λdx. λ is the linear charge density.
k: Coulomb constant = 8.98*10^9 Nm^2/C^2
You can write dq as λdx. Furthermore, If you assume that the other extreme of the bar is at origin of the x-axis you can write the integral as follow:
[tex]V=\int_{0}^{2}k\frac{\lambda dx}{x+3}\\\\V=k\lambda \ ln(x+3)|_{0}^{2}=k\lambda (0.510)[/tex]
You replace λ ad k in the last expression:
[tex]V=(8.98*10^9Nm^2/C^2)(\frac{5*10^{-9}C}{2m})(0.510)=11.44\frac{J}{C}[/tex]
hence, the electric potential is 11.44J/C
Explica brevemente, pero con claridad, las semejanzas y diferencias entre: a) Un imán natural y otro artificial. b) Un imán temporal y otro permanente
Answer:
natural magnet is a material where the magnetic domains are aligned in a specific direction
An artificial magnet is a material that is placed in a strong external magnetic field, which causes the magnetic pick-ups of the spins to line up, thus creating a magnetic field in the direction of the external field,
Explanation:
A natural magnet is a material where the magnetic domains are aligned in a specific direction therefore creating a magnetic field in that direction.
An artificial magnet is a material that is placed in a strong external magnetic field, which causes the magnetic pick-ups of the spins to line up, thus creating a magnetic field in the direction of the external field, when the external field turns off the Material slowly returns to the random (paramagnetic) state in a given time as it detaches from the interaction of the material's spins.
A permanent magnet is a magnet where the spies are aligned in the molecules and therefore the Ferromagnetic state is maintained over time.
In a temporary magnet the state of lowest energy is paramagnetic and therefore the spins go into this disordered state to decrease the internal energy and the magnet disappears at the source of the relaxation time of the spins.
what are the dimensions of the rectangle
Answer:
A rectangle has two dimensions:we can measure its length and,perpendicular to that,its width.
Explanation:
You arrive in my class 45 seconds after leaving math which is 90 meters away. How fast did you travel?
Answer:
2m/s
Explanation:
speed = distance÷time
speed =90÷45=2m/s
What evidence can you see of women and men's changing roles over the past few
generations in the US?|
Samanthawalks along a horizontal path in the direction shown the curved path is a semi circle with a radius of 2 m while the horizontal part is for me what is the magnitude of displacement
Answer:
Explanation:
Samantha walks along a horizontal path in the direction shown the curved path is a semi circle with a radius of 2 m while the horizontal part is for me what is the magnitude of displacement
Displacement is given by the straight line distance between P and Q. Displacement will be length of straight line joining P and Q
a semi circle with a radius of 2 m
Length of this straight line=4+diameter
=4+(2*2)
=8 m
An elephant pushes with 2000 N on a load of trees. If it takes the elephant 45 seconds to move trees 15 meters, how much power did the elephant generate?
Answer:
Power generate by elephant = 666.67 W
Explanation:
Given:
Force = 2,000 N
Change in time = 45 Seconds
Distance = 15 meter
Find:
Power generate by elephant ?
Computation:
⇒ Work Done = Force × Distance
⇒ Work Done = 2,000 × 15
⇒ Work Done = 30,000
⇒ Power = Work Done / Time taken
⇒ Power generate by elephant = 30,000 / 45 seconds
⇒ Power generate by elephant = 666.67 W
Do u think the benefits of nuclear energy outweigh the dangers
Answer:
While there is no such thing as 100 percent safe, having nuclear energy is much safer than you think. It's thousands of times safer than conventional coal and other fossil-fuel-derived energy, not to mention the specter of environmental disaster from continued use of carbon-based energy sources.29 may. 2011
Explanation:
I hope it helps you
Un recipiente contiene 2,5 moles de gas propano. Calcula, utilizando la definición de mol, cuántas moléculas de propano (C3H8) contiene ese recipiente.
POR FAVOR NO LO ENTIENDO Y CON SUS OPERACIONES PLISS
Answer:
1.505*10^{24} molecules
Explanation:
The number of molecules is independent of the subtance, and only depends on the number of moles.
To calculate the number of molecules in a substance with n moles you use the following formula:
[tex]m=nN_A[/tex]
m: number of molecules
NA: Avogadro's number = 6.02*10^23 molecules/mol
n: moles of the substance = 2.5 mol
You replace the values of n and NA in the equation for m and you obtain:
[tex]m=(2.5mol)(6.02*10^{23}molecules/mol)\\\\m=1.505*10^{24}\ molecules[/tex]
hence, the number of molecules is 1.505*10^24
PLEASE HELP ME!
A student notices that when calcium chloride is placed in water, the test tube feels warm. What kind of reaction has taken place?
A. Combustion Reaction
B. Endothermic Reaction
C. Exothermic Reaction
D. Endergonic Reaction
Answer:
C. Exothermic Reaction
Explanation:
Let's go through the choices
A. Combustion - Combustion is a highly exothermic / redox reaction which produces light and heat (i.e basically it bursts into flames). In the description, the only reaction is that it feels warm, hence this is not the answer.
B. Endothermic - Recall that endothermic reactions absorbs heat and thus cools the surroundings thereby making test tube feel cooler. this is obviously not the case so this is not the answer.
C. Exothermic - Recall that exothermic reactions releases heat and thus causes the surroundings thereby making the test tube feel warmer (or hotter in some cases). This describes our situation so THIS IS THE ANSWER.
D. Endergonic reactions require an input of energy from an external source that is adsorbed by the reaction (for example if heat was applied by an external source). In this case, there is no mention of additional energy sources. Hence this is probably not the answer.
which of the following is contact force
a)magnetic force
b)friction
c)gravity
d electrical force
Answer:
friction
...............
Answer:
Friction
Explanation:
Friction, air resistance, and tension are other examples of contact forces. Straight from the book. Please give branliest
What would happen to a current in a circuit if the resistance is multiplied by four
Answer:
The current would be multiplied by 1/4, meaning it is reduced by 3/4 of itself.
Explanation:
This is because when the resistance increases, the current decreases along with it.
What is the formula for velocity???
Explanation:
divide the distance by the time it takes to travel that same distance, then add your direction to it.
Or change in displacement divided by change in time.
why are the group 17 elements the most reactive of the nonmetal elements a)they are the biggest elements b)they have the fewest electrons c)they are located on the farthest right side of the periodic table d)they require only one electron to fill their outer energy level
Answer:
I think the answer is D-they require onky one electron to fill their outer energy level.
Wolves, which are top predators, were eliminated from Yellowstone National Park in the 1930s. In 1995, wolves were reintroduced into Yellowstone. During the period in which wolves were absent from Yellowstone, which MOST likely occurred?
A. an increase in competition for food resources among small prey
B. a greater opportunity for primary producers to flourish
C. an increase in the population of tertiary consumers
D. a greater balance of predator-prey relationships
Answer:
The answer is E
Explanation:
Wolves died off from the rona virus back in the 1930s so when they came back they brought C- 19 with them
A boat at anchor is rocked by waves whose crests are 28 m apart and whose speed is 7 m/s. How often do these waves reach the boat? State your answer in terms of frequency (Hz) and period T (seconds).
Answer:
0.25 Hz
4 s
Explanation:
Speed = wavelength × frequency
7 m/s = 28 m × f
f = 0.25 Hz
Frequency = 1 / period
0.25 Hz = 1 / T
T = 4 s
The baker needs 9 eggs, 6 cups of flour, 3 cups of sugar, and 3 sticks of butter to make a total of 3 cakes.. The baker only has 2 sticks of butter. That means the butter is the ___________ because the baker can only make 2 cakes!
Question 19 options:
Product
Reactant
Limiting reactant
Spontaneous reactant
Answer: Limiting reactant
Explanation:
The limiting reactant is a reactant will get completely consumed up in the reaction. This reactant being in low concentration will lead to the formation of limited amount of product.
In the given situation, since the butter cakes are required to be 3 sticks for making 3 cakes but only 2 cakes are available thus the butter stick is the limiting reactant.
Examples of pure substances are elements and _________.
A. Mixtures
B. Compounds
Answer:
b
Explanation:
Answer:
b
Explanation:
trust
what does waining mean?
Answer:
(of the moon) have a progressively smaller part of its visible surface illuminated, so that it appears to decrease in size.
Explanation:
scientific notation for 836
Answer:
8.36e2
Explanation:
Use a scientific calculator
Its notation is written as :
8.36 x 10^2
If your mass on Earth is 71Kg, what is your weight on Earth to two decimal places?
Answer:
If your mass on Earth is 71 Kg, what is your weight on Earth to two decimal places?
your mother you uncultured swain how dumb can you be go jump off a bridge ETAY who even names there child ETAY more like EBAY
Two tuning forks are played at the same time. One has a frequency of 176 Hz and the other is 178 Hz. How many beats per second are heard?
Answer:
There is 2 beats per second.
Explanation:
You have to subtract them to find your answer and 178 - 176= 2
Explain your thinking. What definition, rule, or reasoning did you use to decide
whether something is a solid?
Answer:
Explanation:
A Solid is one of the three main states of matter. By definition a solid is something whose molecules are so densely packed together that it allows it to keep its shape. Therefore if the item has a definite shape that does not change on it's own it is a solid. As opposed to a liquid which will take and fill the shape of it's container.
