Answer:
no
Explanation:
HIV transmits only during fluid interaction, only if she Heather had an cut exposing the inner skin then HIV can be transmitted
half life, for my physics but pretty sure it involves maths. you don’t have to do them all i’m just confused how to work it out.
I probably don't have to tell you that the other answer is nonsense, but I'll do it all the same, just in case... Half-life is defined as the time it takes for some radioactive substance to decay to half its original amount.
If it takes n half-lives for some substance with a starting amount of A to decay to a final amount of B, then
[tex]B = \dfrac{A}{2^n}[/tex]
1. If the half-life is x, then after 1 half-life, 5000 units of this substance decays to 2500 units. After another half-life, this decays to 1250. After another, this in turn decays to 625.
So 3 half-lives are required.
In terms of the equation above, we solve for n such that
[tex]625 = \dfrac{5000}{2^n} \implies 2^n = 8 \implies n=3[/tex]
since 2³ = 8.
2. Count how many times you halve 15,000 to end up with 3750:
15,000/2 = 7500
7500/2 = 3750
===> 2 half-lives
In other words,
[tex]3750 = \dfrac{15,000}{2^n} \implies 2^n = 4 \implies n=2[/tex]
3. After 1 half-life, you would end up with
12,000/2 = 6000
and after another half-life,
6000/2 = 3000
i.e.
[tex]\dfrac{12,000}{2^2} = \dfrac{12,000}4 = 3000[/tex]
4. After 1 half-life, you have
26,000/2 = 13,000
After 2 half-lives,
13,000/2 = 6500
After 3 half-lives,
6500/2 = 3250
After 4 half-lives,
3250/2 = 1625
i.e.
[tex]\dfrac{26,000}{2^4} = \dfrac{26,000}{16} = 1625[/tex]
5. If the half-life is 3 years, then 15 years = 3 half-lives.
In the last 3 years, 20,000 would have decayed to 10,000.
In the second-to-last 3 years, 40,000 would have decayed to 20,000.
In the first 3 years, 80,000 would have decayed to 40,000.
i.e.
[tex]\dfrac{x}{2^3} = 10,000 \implies x = 8\times10,000 = 80,000[/tex]
An experiment is designed to investigate the relation between the pressure and temperature in a tank that has a constant volume and mass. (The equation of state for air is pV=m R T, where p is the pressure, V is volume, m is mass, R is the gas constant, and T is the temperature.) A polynomial relation was suggested for the relation between p and T. You noticed that as you increase the order of the polynomial the error between the curve fit and the measured data decreases. What polynomial order is best to use
Answer:
3rd order polynomial
Explanation:
Given that the increase in the order of the polynomial the error between the curve fit and measured data will decreases hence :
The polynomial order that is best to use is the 3rd order polynomial, this is because using a 3rd order polynomial will produce a less variance and a low Bias
A roller coaster goes from 10 m/s to 30 m/s in 5 seconds. What is it's acceleration?
Vf-Vi/T
Which type of reproduction uses gametes?
sexual
asexual
Water can be found in solid, liquid, and gaseous states. Which two processes would result in water changing to water vapor (or steam) when boiled?
deposition and condensation
evaporation and deposition
sublimation and evaporation
condensation and melting
Answer:
sublimation and evaporation
Explanation:
evaporation is from liquid to gas and sublimation is solid to liquid, as water vapor is a gas both of these methods could be used
A car moving with a speed of 35 m/s sees a child standing in the
middle of the road. The driver of the car applies brakes and brings the
car to rest in 5 sec, just in time to save the child. Calculate the average
stopping force of the vehicle, if the mass of vehicle and the driver is
300 kg.
Answer:
2100 N
Explanation:
[tex]v = u + at \\ 0 = 35 + a(5) \\ a = - 7m {s}^{ - 2} \\ \\ net \: force \: = ma \\ = (300)(7) \\ = 2100 \: newtons[/tex]
Use the information to answer the following question.
Hot air balloons use a flame that can turn on and off to heat air inside a large balloon. The balloon is attached to a basket which can carry people or cargo as it is lifted off the ground and floats in the air.
Using what you know about gases, predict which approach would allow the hot air balloon to reach the highest height?
A.
Turn on the flame for 10 seconds each minute for 10 minutes to increase the density of the air inside the balloon.
B.
Turn on the flame for 10 seconds each minute for 2 minutes, and cut a large hole in the balloon material to allow excess air out.
C.
Turn on the flame for 30 seconds each minute for 2 minutes, and cut a large hole in the balloon material to allow excess air out.
D.
Turn on the flame for 30 seconds each minute for 10 minutes to decrease the density of the air inside the balloon.
Answer:
The answer is B. :)
Explanation:
The hot air balloon reaches the highest height turn on the flame for 10 seconds each minute for 2 minutes and cut a large hole in the balloon material to allow excess air out.
What is a hot air balloon?Because hot air rises, hot air balloons work. By using the burner to heat the air inside the balloon, it becomes lighter than the cooler air on the outside.
As a result, the balloon floats upwards, as if it were in the water. Obviously, allowing the air to cool causes the balloon to slowly deflate.
Hot air balloons use a flame that can turn on and off to heat air inside a large balloon. The balloon is attached to a basket that can carry people or cargo as it is lifted off the ground and floats in the air.
Turn on the flame for 10 seconds each minute for 2 minutes, and cut a large hole in the balloon material to allow excess air out.
Hence the hot air balloon reaches the highest height turn on the flame for 10 seconds each minute for 2 minutes and cut a large hole in the balloon material to allow excess air out.
To learn more about the hot air balloon refer to the link;
https://brainly.com/question/11178349
Underground caves can form in limestone through deposition.
A.) False
B.) True
Answer:
I think the answer is option B
Please help!!!!!!!!!
What help do you want? If you tell, I may help you.
1. Matter is made up of small particles called
2. What is the volume of this rectangular prism?
cm^3
Calculate the volume of this regular solid.
6 cm
5 cm
9 cm
Photosynthesis occurs in a plant cell's
Cellular respiration occurs in a plant or animal cell's
Answer:
Photosynthesis occurs in the organelle, chloroplast .
Cellular respiration occurs in a plants or animals mitochondria.
Explanation:
Hope this helps! :)
One object is at rest, and another is moving. The two collide in a one-dimensional, completely inelastic collision. In other words, they stick together after the collision and move off with a common velocity. Momentum is conserved. The speed of the object that is moving initially is 25 m/s. The masses of the two objects are 3.0 and 8.0 kg. Determine the final speed of the two-object system after the collision for the case when the large-mass object is the one moving initially and the case when the small-mass object is the one moving initially.
Large object moving, small object at rest:
v = 18.18m/s
Small object moving, large object rest:
v= 6.81m/s
Explanation:
p = mv
m1•Vi1 + m2•Vi2 = m1•Vf1 + m2•Vf2
First Scenario (large object moving):
For small object,
p=mv
p= 3kg • 0 = 0
For large object,
p= mv
p= 8kg • 25m/s = 200kg•m/s
Combined,
p1+p2 (small object + large object) = 200m/s
After the collision, there is one mass,
new mass is 8kg + 3kg = 11kg
So now , p = mv again. In this case
200m/s = (11kg)•v
v = (200kg•m/s)/(11kg) = 18.18 m/s
Second Scenario (small object moving):
p1v1 = 3kg•25m/s = 75kg•m/s
p2v2 = 8kg•0 = 0
p1v1 + p2v2 = 75kg•m/s
New mass = 8kg+ 3kg = 11kg
p = mv
75kg•m/s = 11kg•v
v = (75kg•m/s)/11kg = 6.81m/s
1.
Which type of tide would result from this arrangement of the Sun, Moon and Earth? ________
2. How are Spring Tides different from Neap Tides? Give at least 2 reasons ________
3. Which phase of the moon comes after the one shown in the diagram below? _______
4. Which type of tides has very large high tides and very small low tides? _________
5. Which of these models shows the position of the sun moon and Earth that will have the
LARGEST effect on the tides? _________
the first picture is for number 1
the second on is for 3
the third is for 5
Please do this for everyone that needs it
Answer:
1. High Tide
2. I don't know
3. Waning Crescent
4. Spring Tides
5. I don't know
Explanation:
Answer:
1.neap tide
2.spring tides occur when the earth and the sun are in line with the new or full moon
3.first quarter
4.spring tides
5. its the diagram G
Explanation:
Which choice best describes how scientists learn new information during investigations?
A. During investigations, scientists learn new information, ask questions, and then make observations.
B. During investigations, scientists make observations, use their observations to ask questions, and learn new information.
C. During investigations, scientists make measurements, collect and record information, ask a question, and then make observations.
During investigations, scientists collect and record data and then make observations.
Answer:
C
Explanation:
During investigations a scientist needs to observe, investigate, collect data and put together the information they collect.
A car traveled 210 km in 1.5 hrs, what was the car's average speed?
Answer:
140km/h
Explanation:
Average speed= Distance/Time
= 210/1.5
= 140 I'm/h
Density is the ____ of a substance. The density of a substance is _____ if its particles are packed tightly together. Hardness shows __________.
Answer:
degree
liquid
mass-volume
Explanation:
HELPP ME IN PHYSICS +15 POINTS!!
But a right answer not links or I’ll report. -_-
The answer shud be 31 . 14m
2 points
What element in this equation indicates that this is a combustion reaction: CH4(g) + 2 O2(g) — CO2(g) + 2 H2O(g)? i
Help Me Fast Please!!
A piano tuner hears a beat frequency when using a tuning fork to tune a piano wire. The piano tuner should adjust the tension in the wire to
increase the amount of interference and increase the beat frequency.
increase the amount of interference and decrease the beat frequency.
decrease the amount of interference and decrease the beat frequency.
decrease the amount of interference and increase the beat frequency.
Answer:
There is only a beat frequency when the frequency heard (perhaps a tuning fork) is different from the frequency from the object in question (piano string, etc.).
The beat frequency equals the difference of the frequencies of the sources.
The piano tuner should adjust the tension in the wire to: C. decrease the amount of interference and decrease the beat frequency.
A wave can be defined as a disturbance created in a medium, which progressively transports energy from a source to another location without the transportation of matter.
Basically, some of the phenomenon and properties associated with waves include the following:
Doppler shift (Doppler effect)ReflectionRefractionDiffractionInterferenceAn interference refers to a phenomenon in which two (2) waves meet while traveling along the same medium and they superpose to produce a resultant wave with either a lower, greater, or the same amplitude.
In this scenario, a beat frequency is being heard by a piano tuner when using a tuning fork to tune a piano wire. Thus, the piano tuner should adjust the tension in the wire, so as to decrease the amount of interference and the beat frequency.
Read more: https://brainly.com/question/14929897
Which model could represent a neutral atom of nitrogen? 2 3 4 A. 1 B. 3 C. 4 D. 2.
Answer:
B
Explanation:
because it has more power
The Model A represents a neutral atom. hence option A is correct.
What is Atom ?Atom is smallest entity of a body. Body is made up of atoms. it is basic building block of a body. An atom consist of electrons, protons and neutrons as sub atomic particle. whole mass of the atom is concentrated at the center of the atom which we call it as nucleus, nucleus consist of proton and neutron. Electron revolve around the nucleus at determined(fixed) orbit. Total number of protons in the atom decides the atomic number and the elements in the periodic table. The electrons which are completely filled orbitals are called as core shell electrons and which are not filled completely are called as valence electron. valence electrons are responsible for physical and chemical properties of the element. Elements which are on same column in periodic table have same number of valence electrons . Hence they have same properties.
Atomic number of Nitrogen is 7. Hence neutral atom of nitrogen has 7 electrons in his orbits.
Hence option A is correct.
To know more about Atom :
https://brainly.com/question/30898688
#SPJ5.
The weather map shows air pressure in Millibars. Which set of conditions 10 por
best describes the weather at the area of lowest air pressure?"
1004
1004
1008
1008
1008
1004
41004
(1008
1-000
1000
1000
996 L
1-004
1004
1000
1000M
2008
2004
-1004
1008
A. Bright sun with no wind
O B. Mostly sunny with no winds
O C. Partly cloudy with no wind
O D.Overcast skies with strong winds
I think the answer for the following question is A.
Look at the diagram of a solar eclipse.
A solar eclipse with labels 1 through 4. 1: The moon. 2: A location on Earth directly in line with the center of the Sun and Moon. 3: A location above 2. 4: A location below and right of 2.
At which location is the solar eclipse viewed in totality?
1
2
3
4
Answer:
at location 4
Explanation:
it is because the solar eclipse happens when the moon is covering the sun
How are magnetic field line
models helpful?
Answer:
Explanation:
En física, las líneas de campo son una ayuda para visualizar un campo electrostático, magnético o cualquier otro campo vectorial estático
An object is lifted against gravity from the floor to a tabletop. This is an example of
Answer:
Work done against gravity in lifting an object becomes potential energy of the object-Earth system. The change in gravitational potential energy, ΔPEg, is ΔPEg = mgh, with h being the increase in height and g the acceleration due to gravity.
Explanation:
what is resistance to motion called?
Answer:
it's friction
Explanation:
100% sure about that
A test tube has a diameter of 3cm how many turns would a piece of thread of length 90.42cm make round the test tube
Answer:
9.59 turns
Explanation:
A test tube looks like cylinder, we can say it has a cross section of circle- like. Then the circumference of the test tube can be determined,Then use it to divide length of the string which answered the question.
Circumference of the tube=( π d)
Where d= diameter
π= 3.142
If we substitute the values, we have
= (3× 3.142)= 9.42cm
length of the string= 90.42cm
Circumference of the tube= 9.42cm
Number of turns around the test tube=
=( length of the string) /Circumference of the tube
=(90.42 ÷ 9.42)
= 9.59cm
Two forces one of 12N and another of 5N act on a body in such away that they makes an angle of 90 digre with each other,what is the resultant?
Answer:
Sorry I didn't know the answer
A man pulls a sled at a constant velocity across a horizontal snow surface . If a force of 80 n is being applied to the sled at an 53 degree to the ground . What is the force of friction between sled and snow
Answer:
Explanation:
The force of 80N is applied on sled at 53⁰
Its horizontal component = 80cos53
= 48.14 N .
Its horizontal component will pull forward the sled and friction will prevent its forward motion . As sled is moving with constant velocity , net force on it is zero .
Hence forward push = frictional force
Frictional force = 48.14 N.
which of the following power plants does not use thermal energy to produce electricity?
a) fossil fuel power plant
b) nuclear power plant
c) geothermal power plant
d) hydroelectric power plant
Answer: d
Explanation:
the girl has a weight of 72N on moon.what will be the mass and the weight of the girl on earth.(use g earth=10m/s 2/g 9 moon=1.6m/s 2)
Answer:
F(m)= mg(m)
m=F(m)/g(m)=72/1.6=45kg
F(e)= mg(e)= 45 x 10 m/s= 450N