Answer:
Let N0 be the initial atoms of Be11
N0 / 2^1 = N0 / 2 Number of Be11 after 1 half-life
N0 / 2^2 = N0/ 4 Number of Be11 after 2 half-lives
30/13.81 = 2.17 half lives
N0 / 2^2.17 = N0 / 4.51 = .222 N0 or 22.2 % of atoms remain
The percentage of the initial sample that will remain after 30.0 s is 22.2 % of atoms remain.
What is half-life?A half of existence is the duration required for something to reduce in size by half. The phrase is most frequently used in reference to radioactive decay, which takes place as unstable atomic particles weaken. There are 29 known factors that can operate in this way.
Every chemical has a unique half-life. Since carbon-10, for instance, has a half-life of only 19 seconds, it is impossible for this isotope to be found in nature.
Let No of the initial atoms of Beryllium-11
No / 2¹ = N0 / 2 Number of Be11 after 1 half-life
No / 2² = N0/ 4 Number of Be11 after 2 half-lives
30 / 13.81 = 2.17 half lives
No / 2²·¹⁷ = N0 / 4.51 = .222 N0 or 22.2 % of atoms remain
Therefore, the percentage of the initial sample will remain after 30.0 s is 22.2 %.
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A truck covers 40 km with an average speed of 80km/h. Then it travels another 40 km with an average speed of 40 km/h. The average speed of the truck for the total distanced covered is:
Answer:
Average speed = 53.33 km/h
Explanation:
Below is the calculation for the average speed:
Given the average speed of for first 40 km = 80km/h
Time taken to cover the first 40 km = Total Distance / average speed
Time taken to cover the first 40 km = 40 / 80 = 0.5 hours
Given the average speed of for next 40 km = 40km/h
Time taken to cover the next 40 km = Total Distance / average speed
Time taken to cover the next 40 km = 40 / 40 = 1 hours
Now the average speed of the tuck to cover total distance:
Average speed = Total distance / Total time
Average speed = (40 + 40) / (0.5 + 1)
Average speed = 53.33 km/h
CAN ANYONE HELP WITH THESE QUESTIONS :,] PLS IS URGEN IM SO CLOSE TO FAILING ALSO ITS SCIENCE PHYSICS I THINK
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The frequency of sound is 200 Hz. What does it mean? Please help me
Explanation:
A wave having a frequency of 200 Hz means that 200 such waves pass through a point per second.
Look at the graph below.
A graph is shown with Absolute magnitude shown on y axis and Surface temperature in degree Celsius shown on x axis. The Dwarf stars are shown along a slanting line from coordinates 30,000 and minus 3 to 10,000 and minus 4. The Main Sequence stars are shown along a slanting line from coordinates 20,000 and minus 2 to 2,000 and minus 6. The giants are shown along a line parallel to the x axis from coordinates 5,000 and 2 to 2,000 and 3. The supergiants are shown along a line parallel to the x axis from coordinates 7,500 and 4 to 2,500 and 4. Point A has coordinates 20,000 and minus 4. Point B has coordinates 2,500 and minus 4. Point C has coordinates 5,000 and 2. Point D has coordinates 7,000 and 4.
Which statement is true about Star A?
a
It is red in color.
b
It is yellow in color.
c
It is four times brighter than the sun.
d
It is four times dimmer than the sun.
Answer:
I'm pretty sure its C
Explanation:
An aluminum-alloy rod has a length of 10.0 cm at 20°C and a length of 10.015 cm at the boiling point of water (1000C). (a) What is the length of the rod at the freezing point of water (0 0C)? (b) What is the temperature if the length of the rod is 10.009 cm? /4mks
Answer:
a. 9.99625 cm b. 68 °C
Explanation:
(a) What is the length of the rod at the freezing point of water (0 0C)?
Before we find the length of the rod, we need to find the coefficient of linear expansion, α = (L - L₀)/[L₀(T - T₀)] where L₀ = length of rod at temperature T₀ = 10.0 cm, T₀ = 20 °C, L = length of rod at temperature T = 10.015 cm and T = 100 °C
Substituting the values of the variables into the equation, we have
α = (L - L₀)/[L₀(T - T₀)]
α = (10.015 cm - 10.0 cm)/[10.0 cm(100 °C - 20 °C)]
α = 0.015 cm/[10.0 cm × 80 °C]
α = 0.015 cm/[800.0 cm °C]
α = 0.00001875 /°C
We now find the length L₁ at T₁ = 0 °C from
L₁ = L₀(1 + α(T₁ - T₀))
So, substituting the values of the variables into the equation, we have
L₁ = L₀(1 + α(T₁ - T₀))
L₁ = 10.0 cm[1 + 0.00001875 /°C(0° C - 20 °C)]
L₁ = 10.0 cm[1 + 0.00001875 /°C × -20° C]
L₁ = 10.0 cm[1 - 0.000375]
L₁ = 10.0 cm[0.999625]
L₁ = 9.99625 cm
(b) What is the temperature if the length of the rod is 10.009 cm?
With length L₃ = 10.009 cm at temperature T₃, using
L₃ = L₀(1 + α(T₃ - T₀))
making T₃ subject of the formula, we have
L₃/L₀ = 1 + α(T₃ - T₀)
L₃/L₀ - 1 = α(T₃ - T₀)
T₃ - T₀ = (L₃/L₀ - 1)/α
T₃ = T₀ + (L₃/L₀ - 1)/α
substituting the values of the variables into the equation, we have
T₃ = 20 °C + (10.009 cm/10.0 cm - 1)/0.00001875 /°C
T₃ = 20 °C + (1.0009 - 1)/0.00001875 /°C
T₃ = 20 °C + 0.0009/0.00001875 /°C
T₃ = 20 °C + 48 °C
T₃ = 68 °C
Which of the following best describes the formation of surf? Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break. As waves enter shallow water, the distance between wave crests (wave length) shortens, increasing the tendency to break.
Answer:
The question above would be written again but this time with options attached to it for comprehension sake:
Which of the following best describes the formation of surf?
A. Waves energy, rebounding from its impact with shore, crashes into oncoming waves, causing them to break.
B. Entering shallow water forces wave energy upward, making the wave crest unstable and causing it to break.
C. A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break.
D. As waves enter shallow water, the distance between wave crests (wavelength) shortens, increasing the tendency to break.
The correct answer is option C (A wave encountering shallow water begins to slow at its bottom, while the top of the wave continues at its previous speed. This causes the wave to break).
Explanation:
Surf could mean crashing waves or breaking waves. Generally, the wave speed is constant in the same medium, however, the wave speed decreases as it enters shallow water which is largely due to the water depth which is relatively small, especially when it encounters the bottom of the shallow water. While the top of the wave overtakes the bottom of the wave, making sure the top of the wave continues at its previous speed.
what is the difference between mechanical advantage and distance advantage?
What If Earth got Kicked Out of the Solar System?
Answer:
We wouldn't have our moon and sun. The earth will be colder and darker
Explanation:
Answer:
mars will become habitabe
Explanation:
true fact and every planet will become close to sun
which of the two bodies a and b in the following graph is moving with higher speed and why
.........................................
pls say it fst its very urgent
A truck hits a brick wall with a force of 100000 kg ms² the truck comes to a stop in 0.5 s what is the impulse
Answer:
Impulse = 50,000 J
Explanation:
Given: force = 100,000 kg ms^2 or N; time = 0.5 s
Unknown: impulse = ?
Equation: impulse = (force)(time)
Substitute: impulse = (100,000 kg ms^2 or N)(0.5 s)
Solution: impusle = 50,000 kg ms^2 or J
A beam strikes an irregular mirror and is reflected as shown below. The angle formed by the incoming beam and the reflected beam is 10 degrees. What is the angle of the mirror's surface (measured against vertical) at the location where the beam strikes the mirror?
A. The mirror's surface is angled 5 degrees upward where the laser strikes it.
B. The mirror's surface is angled 5 degrees downward where the laser strikes it.
C. The mirror's surface is angled 10 degrees upward where the laser strikes it.
D. The mirror's surface is angled 10 degrees downward where the laser strikes it.
Answer:
the correct answer is B
Explanation:
The law of reflection states that the angles of incidence and reflection on a surface are the same, the two rays and the normal are in the same part of the surface.
In this exercise indicate that the angle between the incident and reflected ray is 10, therefore the angle with respect to the normal that is a vertical line at the point of contact of the ray must be 5
Consequently the correct answer is B
What if We Nuke the Moon?
Answer:
chonks of rock will hit the earth and if one astoroid is big enough it can distroy all liofe on earth
Explanation:
Answer:
If we nuke the moon, it won't have any sound and will quickly be stopped from travelling any further than the place we nuked it. If some parts of the moon crack and break, it will be forced down on us (like an asteroid).
Many possibilities can happen but I'm just listing one of them.
se lanza un cuerpo desde el origen con velocidad horizontal de 40 m/s, y con un ángulo de 60º. calcular la máxima altura y el alcance horizontal.
Answer:
1. [tex]h = 244.8 m[/tex]
2. [tex]x = 564.8 m[/tex]
Explanation:
1. La altura máxima se puede calcular usando la siguiente ecuación:
[tex] v_{f}^{2} = v_{0}^{2} - 2gh [/tex] (1)
Where:
[tex]v_{f_{y}}[/tex]: es la velocidad final = 0 (en la altura máxima)
[tex]v_{0_{y}}[/tex]: es la velocidad inicial horizontal en "y"
g: es la gravedad = 9.81 m/s²
h: es la altura máxima =?
La velocidad incial en "y" se puede calcular de la siguiente manera:
[tex] tan(\theta) = \frac{v_{0_{y}}}{v_{0_{x}}} [/tex]
[tex] v_{0_{y}} = tan(60)*40 m/s = 69.3 m/s [/tex]
Resolviendo la ecuación (1) para "h" tenemos:
[tex]h = \frac{v_{0_{y}}^{2}}{2g} = \frac{(69.3 m/s)^{2}}{2*9.81 m/s^{2}} = 244.8 m[/tex]
2. Para calcular el alcance horizontal podemos usar la ecuación:
[tex]x = v_{x}*t[/tex]
Primero debemos encontrar el tiempo cuando la altura es máxima ([tex]v_{f_{y}}[/tex] = 0).
[tex] v_{f_{y}} = v_{0_{y}} - gt [/tex]
[tex] t = \frac{v_{0_{y}}}{g} = \frac{69.3 m/s}{9.81 m/s^{2}} = 7.06 s [/tex]
Ahora, como el tiempo de subida es el mismo que el tiempo de bajada, el tiempo máximo es:
[tex] t_{m} = 2*7.06 s = 14.12 s [/tex]
Finalmente, el alcance horizontal es:
[tex]x = 40 m/s*14.12 s = 564.8 m[/tex]
Espero que te sea de utilidad!
Newton discovered
a
that gravity is universal.
b
gravity.
c
that apples hurt when they fall on your head.
d
none of the above
Answer:
b-gravity
Explanation:
newton discovered the general concept of gravity and how it effects earth. he didn't discord it so much as the concept of it.
Newton discovered gravity.
Hope this helps; please mark me brainliest!
Have a wonderful day!
We have a toy gun with a spring constant of 50 N/m. The spring is compressed by 0.2 m. If you neglect friction and the mass of the spring, at what speed will a 2 g projectile be ejected from the gun
Answer:
[tex]31.6\:\mathrm{m/s}[/tex]
Explanation:
The elastic potential energy of a spring is given by [tex]Us=\frac{1}{2}kx^2[/tex], where [tex]k[/tex] is the spring constant of the spring and [tex]x[/tex] is displacement from point of equilibrium.
When released, this potential energy will be converted into kinetic energy. Kinetic energy is given by [tex]KE=\frac{1}{2}mv^2[/tex], where [tex]m[/tex] is the mass of the object and [tex]v[/tex] is the object's velocity.
Thus, we have:
[tex]Us=KE,\\\frac{1}{2}kx^2=\frac{1}{2}mv^2[/tex]
Substituting given values, we get:
[tex]\frac{1}{2}\cdot 50\cdot 0.2^2=\frac{1}{2}\cdot 0.002\cdot v^2,\\v^2=\frac{50\cdot 0.2^2}{0.002},\\v^2=1000,\\v\approx \boxed{31.6\:\mathrm{m/s}}[/tex]
The Keck Observatory is home to the largest Earth-based twin telescopes. The telescopes are located away from city lights, above the clouds where the atmosphere is clear, calm, and dry. In 1999, additional steps were taken to help the telescopes overcome any distortions caused by changes in the atmosphere by adding a laser sighting system. Now, the Keck telescopes can probe distant galaxies and capture images with more detail than even the Hubble Space Telescope. Scientists can now use the Keck telescopes to investigate many questions. What is one question the Keck telescopes would NOT help scientists answer
Answer:
Option D
Explanation:
The options for the question are
a) How do galaxies rotate?
b) What is the weather on Neptune?
c) What is the core of Saturn made of?
d) What other solar systems have planets?
Solution
The Hubble space telescope was designed and integrated into the extraterrestrial system in order to capture information about the surrounding universe. If the Keck Observatory has a better observation capacity than the Hubble space telescope then the scientist would be interested to know the surrounding planets in the solar system.
Hence, option D is correct
Does a feather fall as fast as a rock in a vacuum? If so why?
Answer:
No.
Explanation:
A feather is less dense and thus less force exerted while a rock is very dense thus exerting more force .
explain chamical enargy
Answer:Chemical energy
Explanation:, Energy stored in the bonds of chemical compounds. Chemical energy may be released during a chemical reaction, often in the form of heat; such reactions are called exothermic.
Answer:
Hope this helps
Explanation:
Chemical energy, Energy stored in the bonds of chemical compounds Chemical energy may be released during a chemical reaction, often in the form of heat such reactions are exothermic. The chemical energy in food us converted by the body into mechanical energy and heat .
please help!!
A 1.50 V battery has a 32.0 Ohm
resistor attached. How much
current flows through the circuit?
(Unit = A)
Answer:
0.0469
Explanation:
v=1.50
r=32.0
i=?
equation
i=v/r
i=1.50/32.0
i=0.046875
round to 3 sig figs
i=0.0469
Answer:
.0469
Explanation:
acellus
PLS SHOW WORK ON HOW YOU GOT IT PLS I BEG.
top ( 25 m ) | 75000 j | 0 j | 75000 j
-------------------|---------------|------------|-------------
bottom ( 0 ) | 0 j | 75000j | 75000 j
-------------------|---------------|------------|-------------
h d ( 12.5 m ) | 37500 j | 37500j | 75000 j
-------------------|---------------|------------|-------------
f d ( 5 m ) | 15000 j | 60000j | 75000 j
-------------------|---------------|------------|-------------
Fish are hung on a spring scale to determine their mass (most fishermen feel no obligation to truthfully report the mass). What is the force constant of the spring in such a scale if it the spring stretches 8.50 cm for a 8.1 kg load
Answer:
k = 933.88 N/m
Explanation:
Given that,
The mass of a load, m = 8.1 kg
The displacement in the spring, x = 8.5 cm
We need to find the force constant of the spring. We know that Hooke's law is given by :
F = -kx
Also,
F = mg (Force due to its weight)
So,
[tex]k=\dfrac{mg}{x}\\\\k=\dfrac{8.1\times 9.8}{0.085}\\\\k=933.88\ N/m[/tex]
So, the force constant of the spring is equal to 933.88 N/m.
please help, thank you
4 N to right
( the third option )
...................................
What is the strength of an electric field 0.2 m from a 1.56 x 10-6 C charge?
Answer:
Solution given:
strength of electric field [E]:?
distance[d]:0.2m
charge[Q]=[tex]1.56×10^{-6} C[/tex]
we have
E =K [tex] \frac{Q}{r²}[/tex]
E=[tex]9×10^{9} C[/tex][tex] \frac{1.56×10^-6 C}{0.2²} [/tex]
E=[tex] 3.51×10^{5}[/tex]V/m
strength of electric field : [tex] 3.51×10^{5}[/tex]V/m
Eroded debris that is dropped at the glaciers farthest extent when ice melts at the front of the glacier as seen in the image is called
A. Terminal Moraines
B. Lateral Moraines
c. Gradient
D. Striations
Answer:
A) terminal moraines
Explanation:
Moraines are the rocks and sediments deposited by moving glaciers. Terminal means the end, the furthest the glacier travels. Lateral means what's deposited along the sides of the moving glacier.
Nitrogen gas at standard atmospheric pressure 101.3 kPa, has a volume of 0.080 m3. If there are 3.6 mol of the gas, what is the temperature?
Answer:
271 K
Explanation:
Answer:
The temperature of Nitrogen is 270.85 K.
Explanation:
What is perfect gas ?A gas that follows Boyle's law , Charle's law and law of pressure , is called perfect gas.
Given data;
[tex]P =101.3 KPa , V = 0.08 m^{3} , \\ n = 3.6 mol , R = 8.31\\T = ?[/tex]
By the formula,
P.V = n .R.T
On putting values
[tex]1.013[/tex] x [tex]10^{5}[/tex] x [tex]0.08[/tex] = [tex]3.6[/tex] x [tex]8.31[/tex] x [tex]T[/tex]
So [tex]T =\frac{1.013*10^{5} * 0.08}{3.6 * 8.31}[/tex]
[tex]T =\frac{8104}{29.92}[/tex]
[tex]T = 270.85 K[/tex]
Hence the temperature of Nitrogen is 270.85 K
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The equation provided (from the textbook) first defines the elastic potential energy of a spring as ΔUsp = −(WB + WW), where WB is work the spring does on an attached block and WW is work the spring does on the wall to which it is attached. But WW is ignored in the next step. Why?
Answer:
The given potential energy of the spring is expressed as follows;
ΔUsp = -(WB + WW)
Where;
WB = Th work done by the spring on the block to which it is attached
WW = The work done by the spring on the wall
We recall that work done, W = Force applied × Distance moved in the direction of the force
The work done by the spring on the block, WB = The spring force × The distance the block moves
The work done by the spring on the wall, WW = The spring force × The distance the wall moves
However, given that the wall does not move, we have;
The distance the wall moves = 0
∴ The work done by the spring on the wall, WW = The spring force × 0 = 0 J
Therefore, WW = 0 J, and the spring does not do work on the wall, and WW can be ignored in the next subsequent) steps
Explanation:
You need to pick up a book off the floor and place it on a tabletop. You expend 1.56J of energy to lift the book with a force of 300N. What is the distance?
Work done = Froce × distance
Now, keeping this formula in mimd, we can find the distance as follows;
= 1.56 = 300 × distance
= 1.56/300 = distance
= 156/30000 = distance
= 0.0052 m = distance
Lets convert it into cm so that you don't get troubled seeing it :)
= 1 m = 100cm
= 0.0052 × 100
= 0.52 cm
A net force of 60 N north acts on an object with a mass of 30 kg. Use Newton's second law of
motion to calculate the amount of acceleration the object will experience. Then explain how the
amount of acceleration will change if the net force or the mass of the object increases.
Answer:
Explanation:
F = ma. For us, this looks like
60 = 30a and
a = 2 m/s/s
If the force goes up to, say, 90, then
90 = 30a and
a = 3...if the force goes up, the acceleration also goes up.
If the mass goes up to say, 60, and the force stays the same, then
60 = 60a and
a = 1...if the mass goes up, the acceleration goes down.
An extremely fast-moving charged particle traveling in a magnetic field can radiate X-rays, a phenomenon known as synchrotron radiation. Why is the magnetic field essential to this emission
Answer:
The magnetic field will help to create an electromagnetic radiation which will prevent the charged particle from moving in a constant direction in a straight path.
Explanation: A magnetic field is an area around a particle where magnetic energy is felt or experienced, this ensures that all the charged particle within the magnetic field will be influenced by magnet.
In the highlighted situation, the magnetic field will help to ensure that an electromagnetic radiation is created to synchrotron radiation occurs effectively.
Two people are sitting on wheeled chairs 1 metre apart. Person A is holding a 2kg ball. Person A throws the ball to Person. What happens to person A? Explain.
a.) their chair stays still
b.) chair rolls backwards
c.) chair rolls forwards
Answer:
B - Person A's chair rolls backwards.
Explanation:
This can be seen simply through the Conservation of Momentum. When the ball is thrown to be, the ball's momentum(+m) is transfererd to B, so B's chair moves forward(think about it - it makes sense, doesn't it?), meaning A's chair moves backwards.
So, B.
EXTRA TIP: Try drawing a diagram to help you!