Which of the following is an example of a visual aid? A. a poster B. a pair of glasses C. a set of note cards D. a copy of a written report
Answer:
a pair of glasses
of course
Boats use echo sounders. Pulses of sound waves are reflected by the sea bed and
detected by a sensitive microphone. The time between an echo sounder sending and
receiving a pulse is 0.005 s. The device calculates the depth of the sea, using the speed
of sound in sea water, which is 1500 m/s.
Use this information to calculate the depth of the sea. Show your working.
Answer: depth = 3.75 m
Explanation:
Taken the speed of the sound in sea to be V = 1500 m/s
The time between an echo sounder sending and receiving a pulse is 0.005 s. That is,
Total time T = 0.005
Formula for echo is:
V = 2X/T
Where X = distance covered
Substitute V and T into the formula
1500 = 2X/0.005
Cross multiply
7.5 = 2X
Make X the subject of formula
X = 7.5/2
X = 3.75 m
Therefore, the depth of the sea is 3.75 m
Which of the following is NOT a vector quantity?
(A) Acceleration
(B) Average velocity
(C) Linear momentum
(D) Potential energy
(E) Force
Answer:
D
Explanation:
Acceleration has both magnitude and direction. because velocity is vector quantity
average velocity is vector
linear momentum = mass× velocity
therefore it's also vector
force = mass× acceleration
acceleration is vector therefore force also vector
potential energy= mgh
energy in any form is scaler quantity therefore potential energy too is a scaler quantity.
What is general relativity
Calculate the wavelength of a nitrogen molecule moving at a speed of 523m/s.
Answer:
The de-Broglie wavelength of the nitrogen molecule is 0.0272 nm
Explanation:
The mass, m, of the nitrogen molecule, N₂ = 14.0076u = 28.0152 × 1.66 × 10⁻²⁷ kg
[tex]v_{rms}[/tex] of N₂ = 523 m/s
The de-Broglie wavelength is given as follows;
[tex]de-Broglie \, wavelength = \dfrac{h}{m\times v_{rms}}[/tex]
Where:
h = Planck's constant = 6.62607004 × 10⁻³⁴ m²·kg/s
Plugging in the values, we have;
[tex]de-Broglie \, wavelength = \dfrac{6.62607004 \times 10^{-34}}{28.0152 \times 1.66 \times 10^{-27}\times 523} = 2.72\times 10^{-11} \, m[/tex]
Hence, the de-Broglie wavelength of the nitrogen molecule = 0.0272 nm.
Question 10 of 10
2 Points
Which of the following best describes how the Federal Reserve Bank helps
banks during a bank run?
A. The Federal Reserve Bank acts as an insurance company that
pays customers if their bank fails.
B. The Federal Reserve Bank regulates exchanges to prevent the
demand for withdrawals from rising above the required reserve
ratio.
C. The Federal Reserve Bank has the power to take over a private
bank if customers demand too many withdrawals.
D. The Federal Reserve Bank can provide a short-term loan to banks
to prevent them from running out of money.
Answer:
D. The Federal Reserve Bank can provide a short-term loan to banks
to prevent them from running out of money.
Explanation:
A bank run occurs when a large number of depositors withdraw their deposits simultaneously from a bank.
As the number of withdraws increases, the available cash in the bank decreases until a point that the bank can't give depositors their money.
In these situations, The Federal Reserve Bank acts as a lender of last resort that helps to reinforce the effect of deposit insurance, and to reassure bank customers that they will not lose their money.
how does the direction of acceleration compare with the direction of the net force that produces it
Answer:
Explanation:
The direction of the acceleration is in the same direction as the net force causing it. F = ma is actually a vector equation in which f and a are both vectors and m is a scalar constant.
Do you think a population besides the moon jellies’ consumer population (sea turtles) and resource population (zooplankton) could have caused the moon jelly population to increase in size?
Answer:
I didn't quite understand your question, but the moon jelly population will increase if there are either more zooplankton or less sea turtles.
More zooplankton means more food => higher population
Less sea turtles means that the moon jelly will be lest often consumed => higher population
Answer: Yes because the Orca will start to eat the moon jellies
Explanation: When the Sea Turtles start to get very low on population the Moon jellies are next in line also the sea turtles eat the moon jellies and since they eat the moon jellies the sea turtle has a bit of that taste in them so they will taste alike to the sea turtles.
Which of the following statements best describes the second law of
thermodynamics?
A. Heat flows spontaneously from hot to cold, and entropy
decreases.
B. Heat flows spontaneously from hot to cold, and entropy increases.
C. Heat flows spontaneously from cold to hot, and entropy increases.
D. Heat flows spontaneously from cold to hot, and entropy
decreases.
Answer:
B
Explanation:
Heat flows from hot to cold to lower the temperature of hot areas and increase temperature of cold areas. The end result is that the 2 areas have the same temperature, thus increasing entropy.
Heat flows spontaneously from hot to cold, and entropy increases.
The second law of thermodynamics relates to the entropy of a system. According to the second law of thermodynamics, the total entropy of a system may increase or remain constant in a spontaneous process.
The implication of this is that the entropy of a system never decreases. The entropy of a system increases when heat flows from a hot to a cold body and not vice versa.
Hence, the statement that; "Heat flows spontaneously from hot to cold, and entropy increases" describes the second law of thermodynamics.
What was Neptune's distance from the Sun in 1989?
Answer:
4.5 Billion km :)
Explanation:
thats how it is
Answer:
About 3.8 billions miles from the Sun OR 4.82 kilometers
hope this helped!
Please Help! When drawing free-body diagrams, does the label "centripetal force" get used? Explain why.
Explanation:
No. Centripetal force is a not a force itself, but rather a sum of forces. From Newton's second law:
∑F = ma
∑F = m v²/r
So centripetal force does not get used on a free body diagram.
1. Of the following, the one that is not an example of a suspension is
a. Milk
b. Milk of magnesia
c. Sand in water
d. Sugar in water
2. The word used to represent a chemical reaction is a/an
a. Atom
b. Formula
c. Equation
d. Symbol
3. When two similarly charged objects are brought close together, they
a. Repel each other
b. Have no effect on each other
c. Stick to each other
d. Attract each other
4. An element common to all acids is
a. Chlorine
b. Hydrogen
c. Nitrogen
d. Oxygen
5. Atoms of the same element that differ slightly in mass are called
a. Ions
b. Isotopes
c. Neutrons
d. Positrons
6. In general, salts
a. Contain hydroxide ions
b. Contain hydrogen ions
c. Are ionic compounds
d. Turn blue litmus red.
7. A dye used to test the acidity of a substance is
a. Litmus
b. Magnesium sulfate
c. Sodium chloride
d. Sodium hydroxide
8. The central portion of an atom is called the
a. Electron
b. Nucleus
c. Ring
d. Shell
9. Sugar is poured into a glass of water and stirred. In this example the sugar is the
a. Solution
b. Solvent
c. Solute
d. Alcohol
10. Which of the following is characterized by a sour taste?
a. Bases
b. Acids
c. Salts
d. Compounds
11. Which of the following is characterized by a bitter taste and turn lithmus blue?
a. Bases
b. Acids
c. Compounds
d. Elements
12. The force of gravity on an object is called
a. Density
b. Mass
c. Volume
d. Weight
13. The liquid referred to as the “universal solvent” is
a. Alcohol.
b. Benzene.
c. Oil.
d. Water.
14. A statement that proposes a cause-and-effect relationship between two variables is called:
a. Conclusion.
b. Fair test.
c. Hypothesis.
d. Theory
15. Any substance that has mass and occupies space is called
a. A gas
b. A liquid
c. Matter
d. A solid
16. When the numbers of electrons and protons in a sample of matter are equal, the matter is
a. Insulated.
b. Negatively charged.
c. Neutral.
d. Positively charged.
17. Which of the following is most important when judging the quality of a scientific theory?
a. The quality and reliability of data that support the theory
b. The amount of detail provided in the theory
c. How recently the theory has been published
d. The respectability of the scientists setting forth the theory
18. Substances that cannot be decomposed to any simpler substances are called
a. Compounds.
b. Elements.
c. Mixtures.
d. None of the above.
19. When the air in a bell jar containing a ringing bell is removed, the sound decreases because
a. The removal of the air prevents electric current from flowing
b. Sound cannot travel through the air
c. Sound cannot travel through glass
d. Sound cannot travel in a vacuum
20. An element common to all acids is
a. Chlorine.
b. Oxygen.
c. Nitrogen.
d. Hydrogen.
21. The amount of matter in an object is best expressed by its
a. Density
b. Mass
c. Volume
d. Weight
22. A substance that increases the rate of a reaction is a
a. Liquid
b. Gas
c. Catalyst
d. Solid
Answer: 1. C
Explanation: 2. C
A pot of water is boiled on a stove. Which of the following definitions of the system enables the most straightforward thermodynamic analysis of the process
A. The system is the pot and water.
B. The system is the stove, pot, and water.
C. The system is the building containing the stove.
D. The system is the entire Universe.
Answer:
A. The system is the pot and water.
Explanation:
Thermodynamics is an aspect in science which deals with the applications of heat energy. The useful applications of heat energy to perform work.
In the given question, the pot and water is the system which both absorbs heat energy from the stove. Thus, the system is a closed system since it shares heat energy with its surroundings.
The surrounding of the system extends from the boundary of the pot to the universe.
What is a good analogy for potential energy in a circuit?
Answer: find the answer in the explanation
Explanation: The potential energy in a circuit between two points is the workdone in taking units positive charge from one point to the other in the circuit. Its S.I unit is Joule.
Because voltage of a battery or cell in a circuit is the potential energy difference across its terminal
The potential energy difference between two points is one volt, if the workdone in taking one Coulomb of positive charge from one point to the other is one Joule.
what is the equivalet tempreture of 0 kelvin in celcius scale
HELP NEED IT IN 5 MIN
Answer:
-273.15 degree celcius
Explanation:
Light ray A moves from air to water. Part of ray A is reflected at the air-water boundary. Which arrow in the image is the reflected ray?
E
OA. B
OB.
С
OC.
D
OD. E
Answer:
A. B
Explanation:
The image has been attached.
Reflected ray refers to the ray of light which is reflected back after striking a surface that is non-permeable.
The ray of light which is reflected before the ray touches the surface is said to the incident ray.
According to the given image, ray B is the reflected ray. Ray B is reflected in the air after the ray A strikes at the surface of the water.
B
Explanation:
Since mirrors reflect things, when you shine light at a mirror, it will bounce off of the mirror, or reflect, and shine the opposite direction of where the original light is pointed. The answer would be B because light doesn't go through the mirror, or run along it.
Think of when you through a basketball on the ground. If you bounce it at an angle, it won't just come back to you in the same angle. It will keep bouncing at the same angle you through it. This is pretty much what describes the relationship between ray A and ray B.
HOPE THIS HELPS!!!!!
describe what factors can make it difficult to reintroduce captive animals into their natural habitats.
Answer:
Captive animals are animals that are maintained by people in an enclosed place not allowing them to be free. There are several factors that make it difficult to reintroduce them to their natural habitats like:
-Captive animals don't learn the necessary skills to survive in their natural habitats like hunting skills.
-They are too used to have contact with people which makes them vulnerable to hunters.
-Sometimes these animals are not able to integrate with a wild population.
-It has been found that some captive animals are more susceptible to diseases.
Which graph shows the correct relationship between kinetic energy and speed?
Answer: D
Explanation:
Kinetic energy = 1/2mV^2
From the formula above, we can deduce that kinetic energy is proportional to the square of speed. That is,
K.E = V^2
Graphically, the relationship isn't linear but a positive exponential. Therefore, option D is the correct answer.
Answer:
The correct answer is D.
Explanation:
Hope this helps.
A helicopter travels west at 80 mph. It is moving above a car traveling on a highway at 80 mph. Given this information, you can determine that the helicopter and car are traveling ____.
Select one:
a. in the same direction
b. in different directions
c. at the same speed
d. at the same velocity
Answer:
d. at the same velocity
Explanation:
I will assume the car is also travelling westward because it was stated that the helicopter was moving above the car. In that case, it depends where the observer is. If the observer is in the car, the helicopter would look like it is standing still ( because both objects have the same velocity). If the observer is on the side of the road, both objects would be travelling at the same velocity. Also recall that, velocity is a vector quantity; it is direction-aware. Velocity is the rate at which the position changes but speed is the rate at which object covers distance and it is not direction wise. Hence velocity is the best option.
Answer:
C. At the same speed
Explanation:
I just took the exam and got the answer correct
which type of circuit is shown?
A. closed series circuit
B. closed parallel circuit
C. open parallel circuit
D. open series circuit
Answer:
I think it's D. open series circuit .
Explanation:
hope it helps you!
Help needed.
(1) A small object carrying a charge of
[tex] - 5 \times {10}^{ - 9} \: c[/tex]
experiences a downward force of 10 Newton when placed at a certain point in an electric field
What is the electric intensity at that point.
2. Determine the electric potential due to a charge of
[tex]12 \times {10}^{ - 9} c[/tex]
at a point 6 cm from the charge.
3. A series arrangement of three capacitors of value at 8micro Farahds, 12 micro Farahds and 24 micro Farahds is connected in series with a 90—V battery
(a) Draw and open circuit diagram for this arrangement (b). Calculate the effective capacitance in the circuit
(c) On closed circuit calculate the charge on each capacitor when fully charged
(d) Determine the PD across the 8 micro Farahds capacitors.
Answer:
1. -2×10 ^-9
2. 1800v
3 (ii) 4micro Farhad
(iii) V = 3.60 ×10²
(Iv) 45v
Explanation:
I hope it helps
Why is a device never 100% efficient? *
a) Mechanical Advantage
b) Work
c) Friction
d) Speed Ratio
brainliest for best answer, asap plz
for science lovers!!
An object with a mass of 120 kilograms is moving at a velocity of 30m/s what’s its momentum
Explanation:
Momentum = mass × velocity
p = mv
p = (120 kg) (30 m/s)
p = 3600 kg m/s
Given:
velocity, v = 30m/s
mass, m = 120kg
Therefore, momentum
p = mv
p = 120kg * 30m/s
p = 3600 kgm/s = [tex]3.6 * 10^3 kgms^{-1}[/tex]
What is a simple definition of momentum?A property of a moving body that the body has by virtue of its mass and motion and that is equal to the product of the body's mass and velocity broadly.
What is momentum used for in physics?Momentum is a vector quantity, it has both magnitude and direction. Since momentum has a direction, it can be used to predict the resulting direction and speed of motion of objects after they collide.
Learn more about Momentum here
https://brainly.com/question/904448
#SPJ2
Liquefication occurs when
Answer: Liquefaction occurs when the structure of a loose, saturated sand breaks down due to some rapidly applied loading.
As the structure breaks down, the loosely-packed individual soil particles attempt to move into a denser configuration. Liquefaction most often occurs when three conditions are met:
loose, granular sediment or fill
saturation by groundwater
strong shaking
Answer:
heat is applied
Explanation:with metal and ice
What force is required to give an object with mass 2000 kg an acceleration of
3.5 m/s2?
A. 571 N
B. 7000N
C. 10,500 N
D. 2535 N
Answer:
B
Explanation:
7,000N because the formula for finding force is F=MA (2000x3.5)N=7000N
What is the velocity of the objects position vs time graph
Answer: In a position-time graph, the velocity of the moving object is represented by the slope, or steepness, of the graph line. If the graph line is horizontal, like the line after time = 5 seconds in Graph 2 in the Figure below, then the slope is zero and so is the velocity. The position of the object is not changing
What is the momentum of a man of mass 10kg when he walks with a uniform velocity of 2m/s.
(point stealers will be reported so pls dont do it)
Answer:
[tex]Momentum(p) = 20kgm/s[/tex]
Explanation:
Given
Mass = 10kg
Velocity = 2m/s
Required
Calculate the momentum of the man
Momentum is calculated as thus
[tex]Momentum(p) = Mass(m) * Velocity(v)[/tex]
or
[tex]p = mv[/tex]
So; to solve this question; we simply substitute 10kg for mass and 2m/s for velocity in the above formula;
The formula becomes
[tex]Momentum(p) = 10kg * 2m/s[/tex]
[tex]Momentum(p) = 10 * 2 * kg * m/s[/tex]
[tex]Momentum(p) = 20kgm/s[/tex]
Hence, the momentum of the man is [tex]20kgm/s[/tex]
Help.
Why do scientists believe that global warming is happening?
how much work must be done by frictional forces in slowing a 1000-kg car from 26.1 m/s to rest?
Answer:
Explanation:
Work done by the frictional force is 3.41x10^5 J
It is given that,
Mass of the car, m = 1000 kg
Initial velocity of car, u = 26.1 m/s
Finally, it comes to rest, v = 0
We have to find the work done by the frictional forces. Work done is equal to the change in kinetic energy as per work - energy theorem i.e.
W = −340605 J
or Hence, the correct option is (a).
The temp of equal masses of three different liquids A,BandC are 12°C,19°Cand 28°Crespectively . The temp when A and B are mixed is 16°C, and when Band C are mixed is 23°C.The temp when A and C are mixed is
Answer:
19.1°C
Explanation:
If A and B mix to give 16°C, A has risen by 4°C and B has fallen by 3°C;
If B and C mix to give 23°C, B has risen by 3°C and C has fallen by 5°C;
This means the energy transfered to cause a change of 3°C in B causes a change of 4°C in A and 5°C in C;
We can use this as a ratio (4:5);
The temperature difference between A and C is 16°C;
we add the two parts of the ratio (4+5) to get 9 and divide the temperature difference to get 16/9;
Next we multiply this by one of the parts of the ratio, so with 4, you get 64/9;
This number is the proportional temperature change in A upon mixing;
We then add this to the original temperature of A to get the resultant temperature of the mix like so:
64/9 + 12 = 19.1111...
You can do this alternatively using the other part of the ratio;
We would multiply the 16/9 by the 5 instead of the 4 to get 80/9;
This number is the proportional change in temperature in C upon mixing
Then subtract this from this from the original temperature of C and you should get the same answer:
28 - 80/9 = 19.1111...
