Answer:
At the critical angle the angle of refraction (outside the medium) is 90°
Ni sin θ = Na sin 90° = 1 assuming outside medium is air
sin θ = 1 / Ni where Ni is the refractive of the medium involved
A falling flowerpot has a mass of 5 kg. After falling for one second, it has a speed of 10 m/s. What is its kinetic energy?
KE = 1/2mv²
KE = 1/2 x 5 x (10²)
KE = 250 J
A sample contains 16 g of a radioactive isotope. how much radioactive
isotope remains in the sample after 1 half-life?
After one half-life, 8 g of radioactive isotope will remain in the sample.
What is radioactivity?The act of producing radiation spontaneously is known as radioactivity. This is accomplished by an unstable atomic nucleus that want to give up some energy in order to move to a more stable form.
The following formula is used to compute the number of half lives elapsed:
[tex]\rm N=\frac{N_0}{2^n} \\\\ N=\frac{16}{2} \\\\ N= 8 \ gram[/tex]
Hence,8 gram of radioactive isotope remains in the sample after 1 half-life.
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Answer:
Answer is below
Explanation:
8 g
NAME:
A room has a 60 Watt, a 100 Watt and a 150 Watt light bulb. How much does it
cost to use all the lamps for 2.5 hours at $0.08/ kWh?
E-60
Answer:
$ .0248 or 2.48 cents
Explanation:
60 + 100 + 150 = 310 watts
for one hour = 310 watt- hr or .31 kw- hr
.31 kw-hr * .08 / kw-hr = .0248
Explain how nuclear physics works?
Answer:
Nuclear physics are the study of protons, and neutrons at the center of an atom. This study shows the interactions between atoms, including what holds them together in a small space. Nuclear physics include fission, fusion, and decay.
A crowbar moves a distance of .35 meter to lift a load .05 meters off the ground.
what is the ideal mechanical advantage of the crowbar?
The ideal mechanical advantage of the crowbar will be 0.7.IMA is also equal to the distance traveled by the load divided by the distance traveled by the effort.
What is ideal mechanical advantage?The ideal mechanical advantage of a lever is equal to the length of the effort arm divided by the length of the resistance arm.
The ideal mechanical advantage is found as;
[tex]\rm IMA=\frac{0.35}{0.5} \\\\ IMA=0.7[/tex]
Hence,the ideal mechanical advantage of the crowbar will be 0.7.
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1.
Why does a balloon rubbed on your hair stick to the ceiling? What is this called? Why
does the balloon stay there?
Answer:
Static Electricity.
Explanation:
The rubbing of hair (object) onto the balloon creates a negative charge that is carried by electrons, the electrons will soon build higher to create static electricity, thus keeping it onto the ceiling.
Hope this helps!
While unearthing ancient pottery in the gobi desert, an archaeologist discovers a pot containing a large amount of naturally radioactive americium-241, which experiences alpha decay.
the archaeologist needs to protect himself, but also doesn't want to overheat in the desert sun. in addition to a facemask, what is the most appropriate safety precaution that the archaeologist should take to protect against the alpha particles without overheating?
The most appropriate safety precaution that the archaeologist should take to protect against the alpha particles without overheating by wear a pair of normal leather gloves. Option D is correct.
What is radioactivity?
The act of producing radiation spontaneously is known as radioactivity. This is accomplished by an unstable atomic nucleus that want to give up some energy in order to move to a more stable form.
Radiation is being employed to assist humanity in medical, academia, and industry, as well as to generate power.
Radiation is also important in agriculture, archaeology, space exploration, law enforcement, geology a variety of other fields.
The most appropriate safety precaution that the archaeologist should take to protect against the alpha particles without overheating by wear a pair of normal leather gloves.
Hence, option D is correct.
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When a car moves up a hill with constant
speed, it
A gains both kinetic energy and potential
energy
B
gains both kinetic energy but loses potential
energy
C gains potential energy and no change in
kinetic energy
D
neither gains nor loses potential energy or
kinetic energy
what is weight?how can we measure it
Answer:weight is a vector.
Explanation: It is measured in Newtons (N) and has direction
Answer:
total gravity of mass on earth. it can measured by Newton
Explanation:
I think it will help you. follow me ok .
An ideal pendulum is often discussed when studying simple harmonic motion. what are the conditions needed for an ideal pendulum? check all that apply. gravitational force acts to pull the pendulum’s mass down. the mass of the rod of the pendulum is evenly distributed along the rod. the pivot on which the pendulum swings is frictionless. the pendulum swings through its equilibrium position as a result of inertia. tension acts downward on the pendulum’s mass.
The conditions needed for an ideal pendulum are;
The mass of the rod of the pendulum is evenly distributed along the rod. The pivot on which the pendulum swings is frictionless. The pendulum swings through its equilibrium position as a result of inertiaWhat is an ideal pendulum?An ideal pendulum is a type of pendulum that satisfies the following conditions,
The mass of the pendulum rod should be evenly distributed throughout the rod.The pendulum must move in a frictionless medium.The pendulum must move from the equilibrium position.Thus, the correct statements are second, third and the fourth.
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Answer:
b, c and d are correct ;)
Explanation:
A 2.2kg mass is at the origin. A 4.66kg mass is 3m to its right, and another 4.66kg mass is 3 m to its left. What is the net gravitational force on the 2.2kg mass?
Answer:
zero
Explanation:
The gravitational force between two masses is jointly proportional to the masses and inversely proportional to the square of the distance between them. The constant of proportionality is the universal gravitational constant.
__
In this scenario, the force to the right is matched by an identical force to the left from an identical mass at an identical distance. The magnitudes of the forces are equal, and their directions are opposite. The forces cancel.
The net force on the 2.2 kg mass in the center is zero.
Question 12 (True/Faise Worth 5 points)
The presence of free electrons makes a material a good insulator.
O True
O False
Whats the difference between a lunar and solar eclipse?.
Answer: there is no shadow on the Moon with the solar eclipse.
Explanation: When the Moon passes between the Earth and the Sun, it casts a moving shadow on the Earth's surface, known as a solar eclipse. When the Earth passes between the Sun and the Moon, a lunar eclipse occurs, creating a shadow on the Moon.
What observational fact convinces astronomers that the source of energy in a typical quasar is physically very small?.
Answer:
An extreme redshift of emission lines that indicated high recessional
Ultraviolet light is visible to bumblebees but not humans. if the wavelength of *
uv light is 100nm, what is the frequency of the light?
The frequency of the ultraviolet light given that its wavelength is 100 nm is 3×10¹⁵ Hz
Data obtained from the question Wavelength (λ) = 100 nm = 100×10¯⁹ mVelocity of light (v) = 3×10⁸ m/sFrequency (f) =? How to determine the frequency of the lightThe frequency of the light can obtain as illustrated below:
v = λf
3×10⁸ = 100×10¯⁹ × f
Divide both side by 100×10¯⁹
f = 3×10⁸ / 100×10¯⁹
f = 3×10¹⁵ Hz
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The SI unit for pressure is pascal (Pa). One hectopascal would equal how many pascals? 0. 1 Pa 10 Pa 100 Pa 1000 Pa.
Answer:
100 Pa
Explanation:
"Hecto" prefix is given when a physical quantity generally 100 times the amount of the unit.
1 Pa x 100100 Pa12. A child touches the metal leg of a chair. She says "The
cold is moving to my hand!" How would you (gently) correct
the child in physics terms
A child touches the metal leg of a chair. The temperature of metal leg is moving to her hand.
What is temperature?The temperature is the degree of hotness or coldness when an object is touched.
The metals are generally have less temperature compared to the surrounding temperature. When a child touches the leg of a metal chair, she feel cold, but the physical term is temperature which is moved to her hand.
Thus, temperature of metal leg is moving to her hand.
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an airplane carrying out a parcel drops releases a parcel while travelling at a steady speed of 90 m/s at an altitude of 200 m. caculate a)the time taken between the parcel leaving the airplane and it striking the ground b)the horizontal distance travelled by the parcel in this time. c)the speed at which the parcel strikes the ground
a)The time taken between the parcel leaving the airplane, and it's striking the ground will be 6.38 second
c)The speed at which the parcel strikes the ground will be 62.64 m/sec.
What is speed?Speed is defined as the rate of change of the distance or the height attained. it is a time-based quantity. it is denoted by U for the initial speed while V for the final speed. its SI unit is m/sec.
The given data in the problem is;
Steady speed (V)= 90 m/s
Altitude (h) = 200 m
Time taken (t)=?
horizontal distance travelled(d)=?
Striking speed(V)=?
The striking speed is;
[tex]\rm V^2=U^2+2gh \\\\ V=\sqrt{2gh} \\\\V=\sqrt{2\times 9.81 \times 200} \\\\ V= \sqrt{3924} \\\\ V=62.64 \ m/sec[/tex]
The time taken is found as;
[tex]\rm H = ut + \frac{1}{2} gt^2 \\\\ 200=0+ \frac{1}{2} \times 9.81 \times t^2 \\\\ t=6.38 \ sec[/tex]
Hence, the time taken between the parcel leaving the airplane, and it's striking the ground will be 6.38 second
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Write the relation between mass and weight of a body
Answer:
[tex]\text{Weight} = \text{Mass} \times \text{Gravitational acceleration}[/tex]
Explanation:
Equipment used to measure the volume of the brass pieces
I believe a scale is good
Which of the following is LEAST likely to be the result of a genetic mutation?
A
A horse with a particularly long neck
B
A man with a beard
С
An albino squirrel
D
A plant that produces fewer seeds than normal
Answer:
B. man with a beard
Explanation:
it is not a genetic mutation because it is completely natural and common unlike the other options.
pls complete this table thankyou
Answer:
1)10 m/s
2) 20 m/s
3) 2 s
4) 500 m
5)1000 km/h
Average speed = distance travelled / time.
( note: distance must be in (m) and time in sec, if not then you convert ).
1) average speed = 20/2 = 10mls.
2) average speed = 100/5 = 20 m/s.
3) since we aren't given (time) let's call it x
so we replace the unknown time with x..
average speed = 2/x = 1
then cross multiply
you get x (the unknown time) as 2s {seconds}.
(to check if it's correct just add the time we got back into the equation and see if you would get a erage speed as 1m/s).
4) do the same, replace distance as x or any letter you want )
average speed = x/ 10 = 50
cross multiply
you get x = 500m {meters}
5) (we need to convert km to meters and time to secs because that's what we are working with).
200km = 200,000 m { to convert to meters you multiply the given by 1000, 1km = 1000m).
for 2h, we know that:
60 seconds makes 1 minute
60 minutes makes an hour.
so we multiply 60 by 60 we get 3600mins then we multiply it by 2 to get 7200 secs
so now
Average speed = 200,000/7200 = 27.77 m/s.
Here you go..
hope this helps
Good luck and ace that test.
What is the water division of earth
Answers:
Ocean water 1% freshwater frozen as ice 90% and freshwater9%
Ocean water 47% freshwater 50% and freshwater frozen as ice 3%
Ocean water 97.5% Freshwater frozen as ice 1.5% and freshwater 1%
Ocean water 33.33% freshwater frozen as ice 33.33% and Ocean water 33.33%
Answer:
the third option
Explanation:
Answer:
Ocean water 97.5% Freshwater frozen as ice 1.5% and freshwater 1%
Explanation:
The theoretical capacity of a process is the reciprocal of the theoretical flow time of the process. Do you agree? Explain.
I do not agree with the statement 'theoretical capacity of a process is the reciprocal of the theoretical flow time of the process' because time is only one variable.
What is theoretical capacity?The theoretical capacity of a process can be defined as the ability to perform a given work in a given period of time.
The theoretical capacity of a process is not only dependent on the time that takes to carry out but also on other variables (e.g., temperature, light conditions, etc).
In conclusion, I do not agree with the statement 'theoretical capacity of a process is the reciprocal of the theoretical flow time of the process' because time is only one variable.
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aristotle classified animals on the basis of?
Answer:
Aristotle classified animals on the basis of habitat.
Explanation:
Hope it helps you :)))))
have a good day
I need help with my homework please?
Refer to the attachments
Note that
Like charges attract each other and unlike charges repel each other
When a person sees something, what carries the message from the eyes to the brain?
Answer:
nerves
Explanation:
The optic nerve is the nerve in each eye that carries the signal from your eye to your brain.
Which order is the brightest?
n = 0
n = 1
n = 2
The order of band in which the light becomes the brightest is n = 0.
What is diffraction?
Diffraction is the phenomena of the spreading of waves around obstacles. Diffraction occurs in electromagnetic radiation, such as light, X-rays, and gamma rays, etc.
When light waves pass near a barrier they tend to bend around that barrier and become spread out.
The order bands n=2 becomes dimmest due to the spreading out of the light wave.
Thus, the order of band in which the light becomes the brightest is n = 0.
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n = 0 is correct for edge. :)
write at least five electrical safety rules
a equals thirty five thats why the elephant strted to kiss the cat and the cat went upsidedown and started crying all over the ceiling
Which statement describes the differences between nuclear reactions and chemical reactions?
Nuclear reactions involve changes to electrons, while chemical reactions involve changes to protons and neutrons.
Only chemical reactions can be exothermic.
Chemical reactions can result in new compounds, while nuclear reactions can result in new elements.
Answer:
c on ed
Explanation: