Explanation:
Coal is a fossil fuel and is the altered remains of prehistoric vegetation. The energy we get from coal today comes from the energy that plants absorbed from the sun millions of years ago. In the burning process of coal, carbon dioxide (CO2) is emitted. Humans expel CO2, and plants utilize it every single day. Carbon is a building block for all forms of life and is used in a lot of everyday products.
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands—called coal forests—that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times. However, many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras.
Answer:
look it up of goog le
Explanation:
Muốn đun sôi 200g nước từ 30 độ cần cung cấp nhiệt lượng bao nhiêu :
Answer:
cần cung cấp 70 độ vì nước sôi ở 100°C
Explanation:
3. True or False: A warm-up can include minimal stretching at the end.
Answer:
False.
Explanation:
A warm up is stretching in the beginning.
please answer me fast
Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
Which of the following is a vector quantity? i. Force ii. Velocity iii. Acceleration iv. All of these 5771
Option ( iv ) is the correct answer.
☛ DefinitionA vector quantity the physical quantity that has both direction as well as magnitude.
To what height, h, would the pendulum bob rise after a single swing if it was being released from the height of 0.80 m
Answer:
0.80 m
Explanation:
Neglecting friction, the total mechanical energy of the pendulum is constant.
E = K + U where K = kinetic energy and U = potential energy.
At its release point of 0.80 m, the pendulum bob has a mechanical energy which is equal to its potential energy, since, its initial kinetic energy is zero. By the time the bob swings to the other end, it has a mechanical energy equal to it initial potential energy since total energy is conserved.
Neglecting friction, the pendulum bob would swing back to its original height of 0.80 m since the total mechanical energy is conserved and at its highest point, it is purely potential energy.
So, the height the pendulum bob swings to after release from a height of 0.80 m neglecting fiction is 0.80 m.
Use the equation d=st where d= distance, s= speed, and t= time. If you ride a skateboard at a speed of 8m/s for 12 seconds, how far do you travel
Answer:
96 meters
Explanation:
d = st
d = (8 m/s)(12 s)
d = 96 m
why do black holes have a large gravitational pull that even light cannot escape from
Answer:
Because matter has been squeezed into a tiny space.
Explanation:
According to NASA, this can happen when a star is dying.
A black hole has no more gravity than the same amount of matter in any other form.
But remember that the gravitational forces are stronger as you get closer to the center of the body. The mass of a black hole is packed into such a small size (theoretically zero !) that you can get very close to its center. THAT'S where its gravity is hugely strong.
2. a. in which principle does simple machine works?
Answer:
A simple machine uses a single applied force to do work against a single load force
Ignoring the friction losses. The work done on the load is equal to the work done with the applied energy. The machine can increase the amount of output power, with a corresponding drop in the distance transported by the load.
during a journey, a car travels at 40 km in 2.5 hours, next 62 km in 3 hours, then took a break for 30 minutes, again travelled the last 120 km in 3.2 hours. calculate the average speed of the car during the journey.
good morning how ya'll doing today
Answer:
good
Explanation:
Answer:
fine
Explanation:
make me as brainliast
what was the Cenozoic era
Current is the movement of positive charges called electrons.
A. True
B. False
help pls <33
Answer:
False -> negative charge
Answer:
false
Explanation: electrons are negative charges
protons are positive charges
An object is thrown with velocity 7.1 m s-1 vertically upwards on the Moon. The
acceleration due to gravity on the Moon is 1.62 ms? What is the time taken for the object to return to its starting point?
A 3.5 s
B 4.4 s
C 6.5 s
D 8.8 s
Answer:D
Explanation:
A force of 15N acts on an area of 60m².What is the pressure? *
Answer:
0.25p.a
Explanation:
force=15N area=60m²
so pressure =force/area =15N/60m²=0.25p.a
A scientist studies how air blowing on plants affects their growth. He uses fans to create different amounts of wind and measures the growth of the plants. What would make this experiment more repeatable?
Answer:D.Keeping track of the exact amount of wind on each plant
PLEASE HELP MAX POINTS AND BRAINLIEST!
Look at the graph below.
A graph is shown with Absolute magnitude shown on the y-axis and Surface temperature in degree Celsius shown on the 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 of the following stars is most likely to be red?
a. Star A
b. Star B
c. Star C
d. Star D
i believe it would be Star A since Point A is a dwarf star and dwarf stars are usually most likely to have red coloring
Answer:
Star A
Explanation:
Literally the question has provided the answer itself
Calculation not required.
See the wordings
First star is dwarf star .
Dwarf star is mostly reddish brown or red colored .
Hence star A is the answer
Why does a ship float on water when it weighs about 100tones and why a stone of less than a kg sinks
Answer with Explanation:
Let me answer this in a simple way, since the density of stone is greater than that of water, the stone sinks as the weight of the stone is greater than the weight of water displaced by it. But the ship is designed in such a way that the relative density of the ship always becomes less than that of water. Therefore, the weight of the water displaced becomes equal to the total weight of the ship and thus it floats.
There are many other ways to explain this but this should give you the general idea.
what is equal to 1 hector area
Answer:
Don't Forget To Follow, Brainliest, And Give Me Heart :)
A 2.0kg object is dropped from a height of 30m.
After it drops for 2.0 seconds, what is its kinetic
energy and what is its potential energy?
(Assume no air resistance.)
Answer:
1) The kinetic energy of the object after it drops for 2.0 seconds is approximately 384.9 Joules
2) The potential energy of the object after it drops for 2.0 seconds is approximately 204 J
Explanation:
1) The given mass of the object, m = 2.0 kg
The height from which the object is dropped, h = 30 m
The kinetic energy of the object after it drops for 2.0 seconds = Required
Kinetic energy, K.E. = (1/2)·m·v²
Where;
v = The velocity of the object
The kinematic equation for finding the velocity of the object is presented as follows;
v = u + g·t
Where;
u = The initial velocity of the object = 0
g = The acceleration due to gravity of the object ≈ 9.81 m/s²
t = The time of motion of the object = 2.0 seconds
∴ The velocity after 2 seconds, v ≈ 0 + 9.81 m/s² × 2 s = 19.62 m/s
The kinetic energy, K.E. after 2 seconds as the object drops is given as follows;
[tex]K.E._{(after \ two \ seconds)}[/tex] = (1/2) × 2.0 kg × (19.62 m/s)² = 384.9444 J ≈ 384.9 J
2) The total energy, M.E. of the object at the top, h = 30 m, u = 0, is given as follows;
The total mechanical energy, M.E. = P.E. + K.E.
M.E. = m·g·h + (1/2)·m·u²
∴ M.E. = 2.0 kg × 9.81 m/s² × 30 m + 0 = 588.6 J
M.E. = 588.6 J
Given that the total mechanical energy, M.E., is constant, we have;
At 2.0 seconds, M.E. = 588.6 J , K.E. ≈ 384.9 J, P.E. = M.E. - K.E.
∴ P.E. = 588.9 J - 384.9 J ≈ 204 J
The potential energy after it drops 2.0 seconds, P.E. ≈ 204 J
A rocket travels vertically at a speed of 1200 km/h. The rocket is tracked through a telescope by an observer located 16km from the launching pad. Find the rate at which the angle between the telescope and the ground is increasing 3 min after lift-off. Round your answer to the nearest hundredth rad/hr
Answer:
w = 0.01 t⁻² rad/h
Explanation:
Let's use trigonometry to find the elevation angle of the telescope, we assume that the rocket remains fixed in the telescope.
tan θ = CO / CA
the adjacent leg is CA = 16 km = 16 10³ m
Let's use kinematics to find the height of the rocket
v = y / t
y = v t
this height is equal to the opposite leg
CO = v t
we substitute
tan θ = vt / 16
tan θ = 1200/16 t
tan θ = 75 t
θ = tan⁻¹ ( 75 t )
speed is defined by
w = dθ/dt
w = [tex]\frac{1}{1 + (75 t)^2} \ 75[/tex]
as time increases we can neglect the 1 of the denominator
w = 1/75 t²
w = 0.0133 t⁻²
Using three significant figures
w = 0.01 t⁻² rad/h
for this answer the time must be given in hours
what give negative acceleration ?
Answer:
But negative acceleration means that the rate of change of velocity is negative or velocity decreases. Example: (1) When we apply brakes in a moving car, then negative acceleration acts on it and the car stops. (2) When we throw a ball upwards, then also negative acceleration acts on it.
Explanation:
If it helps you mark me as a brainleast
MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.
define average velocity
Answer:
The average velocity of an object is its total displacement divided by the total time taken. In other words, it is the rate at which an object changes its position from one place to another.
Explanation:
Average velocity is a vector quantity. The SI unit is meters per second. However, any distance unit per any time unit can be used when necessary, such as miles per hour (mph) or kilometer per hour (kmph)
Answer:
the ratio of total displacement by total time taken
Ра:
5. Mass of the earth is 6x10-kg and its radius is 6400km. What is the
mass of a man weighting 977N?
(99.99kg)
ma
Orth
be
Answer:
what do u need help with
Explanation:
Pа: 5. Mass of the earth is 6x10-kg and its radius is 6400km. What is the mass of a man weighting 977N? (99.99kg) ma. Orth be.
The fluid inside the hydraulic jack has a pressure of 30,000 Pa. If the surface of
the piston that is used to lift an object is 0.1 m’in area, how much weight can
the jack lift?
Explanation:
p = F /A
F = P×A
F = 30,000 Pa / 0.1 m²
F = 300,000 N
If a lever lifts a load four times the effort applied and effort distance is 5 times the load distance, calculate its efficiency
Answer:
If effort distance was 4 times, efficiency would be 100%.
Since it takes 5 times for effort distance, efficiency drops to output/input
output is 1*F
input is (1/4*F)*5
so: F/1/5*F/4 = 4F/5F = .8 or 80%
The efficiency of the lever is 80%.
To calculate the efficiency of the lever, we can use the formula for mechanical advantage and efficiency.
Mechanical Advantage (MA) is the ratio of the load (L) to the effort (E) in a lever system:
MA = Load / Effort
Given that the load is four times the effort applied:
Load = 4 * Effort
Also, the effort distance (dEffort) is five times the load distance (dLoad):
dEffort = 5 * dLoad
Now, we can write the formula for efficiency (η) of a lever system:
Efficiency (η) = (Mechanical Advantage / Ideal Mechanical Advantage) * 100%
The Ideal Mechanical Advantage (IMA) is the ratio of the effort distance to the load distance:
IMA = dEffort / dLoad
Substitute the given values into the IMA equation:
IMA = (5 * dLoad) / dLoad
IMA = 5
Now, we can calculate the Mechanical Advantage (MA) using the relationship between the load and effort:
MA = Load / Effort
MA = (4 * Effort) / Effort
MA = 4
Finally, we can calculate the efficiency (η):
Efficiency (η) = (Mechanical Advantage / Ideal Mechanical Advantage) * 100%
η = (4 / 5) * 100%
η = 0.8 * 100%
η = 80%
The efficiency of the lever is 80%.
To know more about efficiency here
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what weight is recorded by a scale when it is placed inside a lift which is in free fall? Enplain.
Answer:
Explanation:
There is no pressure of your feet on the scales, and no pressure of the floor on the scales, so the scales will read zero*. Hence, your weight, in a freely falling lift is zero
If the force on a spring is 1 N and it stretched 0.5 m, what is the spring
constant?
A.4 N/m
B.0.2 N/m
C.2 N/m
D. 0.4 N/m
We know
[tex]\boxed{\sf Spring\:constant(K)=\dfrac{F}{x}}[/tex]
[tex]\\ \sf\longmapsto K=\dfrac{1}{0.5}[/tex]
[tex]\\ \sf\longmapsto K=2N/m[/tex]
Which of the following is required for photosynthesis to take place?
a.
sugar
b.
oxygen
c.
ATP
d.
water
Please select the best answer from the choices provided
A
B
C
D
please answer as quickly as possible
Answer:
D. water
Explanation:
sugar ( glucose ) and oxygen are bi-products
Answer:
(d) water
Explanation:
water is required for photosynthesis to take place .
sugar , oxygen , ATP are not required to take place in photosynthesis.
what is the direction of magnetic lines of force outside the magnet
please mark me as brainiest p
Explanation:
Magnetic lines of force are closed curves. C) Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?
(1 point)
oxygen (O)
lithium (Li)
bromine (Br)
cesium (Cs)
Lithium element contains one electron therefore valence electron will be one.
The highest level of energy is due to valence electrons which are available to the atom.
The calcium has 2 valence electrons which has electrons with high energy.
These energy will be used by the electron during the chemical reaction, and they will either lose or gain valence electron.
Learn more at https://brainly.com/question/24373314
Answer:
calcium
Explanation:
2 electron
