Which best describes the law of conservation of mass?
O The coefficients in front of the chemicals in the reactants should be based on the physical state of the products,
O Products in the form of gases are not considered a part of the total mass change from reactants to products
O When reactants contain both a solid and a liquid, the solid counts toward the overall mass and the liquid does not
O The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
Answers
Explanation:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Related Questions
Three identical train cars, coupled together are rolling east at 2.0 m/s. A fourth car traveling east at 4.0 m/s catches up with the three and couples to make a fourcar train. A moment later the train cars hit a fifth car that was at rest on the tracks, and it couples to make a five car train. What is the speed of the five car train?
Answers
Answer:
The value is [tex]v = 2 \ m/s[/tex]
Explanation:
From the question we are told that
The velocity of the each of the three cars is [tex]u_1 = u_2 = u_3 = 2 \ m/s[/tex]
The velocity of the fourth car is [tex]u_4 = 4 \ m/s[/tex]
The initial velocity of the fifth car [tex]u_5 = 0 \ m/s[/tex]
Generally from the law of momentum conservation we have that
[tex]m_1 u_1 + m_2 u_2 + m_3 u_3 +m_4u_4 + m_5u_5 = [m_1 + m_2 + m_3 +m_4+ m_5]v[/tex]
Given that the cars are identical then their mass will be the same
i.e
[tex]m_1 =m_2 = m_3 = m_4 = m_5 = m[/tex]
=> [tex][u_1 + u_2 + u_3 +u_4 + u_5]m = 5mv[/tex]
=> [tex]2+ 2 + 2 +4 + 0 = 5v[/tex]
= > [tex]v = 2 \ m/s[/tex]
A high-resistance material is used as an insulator between the conductors of a length of coaxial cable. The resistance material, which forms a hollow tube, has an inner radius a and an outer radius b, and the insulator provides a resistance R between the conductors. If a second insulator, made of the same material and having the same length, is made with double both the inner radius and the outer radius of the first, what resistance would it provide between the conductors
Answers
This question is incomplete, the complete question is;
A high-resistance material is used as an insulator between the conductors of a length of coaxial cable. The resistance material, which forms a hollow tube, has an inner radius a and an outer radius b, and the insulator provides a resistance R between the conductors. If a second insulator, made of the same material and having the same length, is made with double both the inner radius and the outer radius of the first, what resistance would it provide between the conductors
a) (In2)R
b) 4R
c) R/(In2)
d) 2R
e) R
Answer: Option e) R is the correct answer.
Explanation:
Given that;
Inner radius = a
Outer radius = b
Conical Cylinder
∫dR = ∫(edr/2πrL)
R = e/2πL In e |ᵇₐ
R = e/2πL In(b/a) ------------- let this be equation 1
Taking a look at the second cone
a' = 2a
b' = 2a
R' = e/2πL In(2b/2a)
{L = L'}
R' = e/2πL In(b/a) -------let this be equation 2
now lets compare the two equation
R = e/2πL In(b/a)
R' = e/2πL In(b/a)
so R' = R
Therefore Option e) R is the correct answer.
The reason why you should always exercise your abdominal during an exercise session is :
(A) because you will be fully warmed up
(B) you can focus on this muscle better
(C) because is the abdominal muscle is needed in all exercises during a workout
(D) because most people do it that way
(E) it does not really matter if you exercise the abdominal first or last
Answers
Of these electromagnetic waves, which has the A Over a unit distance, wave A has three crests and two troughs. The wave begins and ends at the rest position. B Over a unit distance, wave B has two crests and one trough. The wave begins at the rest position and ends at the top of a crest. C Over a unit distance, wave C has four crests and four troughs. The wave begins and ends at the rest position. longest wavelength?
Answers
Answer:
Wave B has the longest wavelength
Explanation:
The wavelength of a wave is the distance between two consecutive points that are in phase.
The wavelength of a wave is also defined as the distance between successive crests or troughs along the z-axis.
A crest is the point of maximum upward displacement whereas a trough is a point of maximum downward displacement.
Comparing the three waves A, B and C over a unit distance.
Wave A:
Wave A has three crests and two troughs. The wave begins and ends at the rest position. There are 2½ successive points in phase in wave A
Therefore, the wavelength = 1/2.5 = 0.4
Wave B:
Over a unit distance, wave B has two crests and one trough. The wave begins at the rest position and ends at the top of a crest. There are 1¼ successive points in phase in wave B
Therefore, the wavelength = 1/1¼ = 0.8
Wave C:
Over a unit distance, wave C has four crests and four troughs. The wave begins and ends at the rest position.
There are 4 successive points in phase in wave B
Therefore, the wavelength = 1/4 = 0.25
Therefore, wave B has longest wavelength
Which of the following is true of changes in momentum?
A small force may produce a large change in momentum by acting over a short time interval.
A large force may produce a small change in momentum by acting over a short time interval.
A small force may produce a large change in momentum by acting on a very massive object.
A small force may produce a large change in momentum by acting over a short distance.
can you please explain why this is the answer as well and how you got it?
Answers
Answer: ⇒ Answer is 3
Explanation: momentum = mass × velocity"A small force may produce a large change in momentum by acting on a very massive object".
THEY HAVEN'T GIVEN US THE TIME PERIOD NOR THE DISTANCE TRAVELED. THEREFORE WE CANNOT ACTUALLY DECIDE IF THE FORCE IS KEPT FOR A LONG TIME OR SHORT TIME. ANYWAYS SINCE THE MASS IS GIVEN AS MASSIVE , THE MOMENTUM SHOULD BE DEFINITELY HIGH.
WHY I SAY OTHERS ARE WRONG:
1) For a small force to give a large change in momentum, it should act for a long time interval.
2) By applying a large force for a short time interval, the change of momentum should be large.
3) Correct answer.
4) Acting over a short distance can be the same as acting over a short period of time.Therefore the distance should be large in order for a larger momentum.
I HOPE IT HELPS!
The true statement is required.
The true statement is A large force the change in momentum may be small acting over a short time interval.
Force is given by
[tex]F=ma[/tex]
m = Mass of object
a = Acceleration = [tex]\dfrac{v-u}{t}[/tex]
t = Time
So, force is
[tex]F=m\dfrac{v-u}{t}\\\Rightarrow F=\dfrac{mv-mu}{t}\\\Rightarrow F=\dfrac{\Delta p}{t}[/tex]
[tex]\Delta p[/tex] = Change in momentum.
If the time taken is small then the force will be large.
The change in momentum can also be small.
So, for a large force the change in momentum may be small acting over a short time interval.
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A chair is thrown upward from a balcony that's 96 ft in the air, at an initial velocity of 16 ft/s.
How many seconds does the chair take to reach its highest height?
Answers
Answer:
t = 6 s
Explanation:
Given that,
A chair is thrown upward from a balcony that's 96 ft in the air, d = 96 ft
The initial velocity of chair, u = 16 ft/s
We need to find how many seconds does the chair take to reach its highest height. Let the time is t.
[tex]t=\dfrac{d}{v}\\\\t=\dfrac{96\ ft}{16\ ft/s}\\\\=6\ s[/tex]
Hence, the chair take 6 seconds to reach its maximum height.
g While hauling a log in the back of a flatbed truck, a driver is pulled over by the state police. Although the log cannot roll sideways, the police claim that the log could have slid out the back of the truck when accelerating from rest. The driver claims that the truck could not possibly accelerate at the level needed to achieve such an effect. Regardless, the police write a ticket, and the drive
Answers
Answer:
The minimum coefficient of static friction required, µ = 0.10
Note. The question is incomplete. The complete question is given below:
While hauling a log in the back of a flatbed truck, a driver is pulled over by the state police. Although the log cannot roll sideways, the police claim that the log could have slid out the back of the truck when accelerating from rest. The driver claims that the truck could not possibly accelerate at the level needed to achieve such an effect. Regardless, the police write a ticket anyway and now the driver court date is approaching.
The log has a mass of m = 929 kg; the truck has a mass of M = 8850 kg. According to the truck manufacturer, the truck can accelerate from 0 to 55 mph in 23.0 seconds, but this does not account for the additional mass of the log. Calculate the minimum coefficient of static friction μs needed to keep the log in the back of the truck.
Explanation:
First, velocity in mph is converted to m/s
1 mph = 0.447 m/s
55 mph ≈ 24.6 m/s
The acceleration of the empty truck is a = v/t = 24.6 / 23 = 1.07 m/s²
Force that can be generated by the truck, F = ma
F = 8850kg * 1.07 m/s² = 9469.5 N
However, with the added mass of the log on it, the acceleration of the truck will become;
a = F / m = 9469.5 N / (8550+929)kg = 0.97 m/s²
Frictional force between the log and the truck = 0.97 m/s² * 929 kg = 901.13 N
Normal reaction on the truck due to the weight of the log, R = mg
R = 929 kg * 9.8m/s² = 9104.2 N
Coefficient of static friction, µ = F/R
µ = 901.13/9104.2
µ = 0.098 ≈ 0.10
Therefore, the minimum static friction required is µ = 0.10
Explain how polarization of a cell increases the cell's internal resistance.
(2
2.
Answers
Answer:
Explanation: The chemical action that occurs in the cell while the current is flowing causes hydrogen bubbles to form on the surface of the anode. This action is called POLARIZATION. Some hydrogen bubbles rise to the surface of the electrolyte and escape into the air, some remain on the surface of the anode. If enough bubbles remain around the anode, the bubbles form a barrier that increases internal resistance. When the internal resistance of the cell increases, the output current is decreased and the voltage of the cell also decreases.
A cell that is heavily polarized has no useful output. There are several methods to prevent polarization or to depolarize the cell.
One method uses a vent on the cell to permit the hydrogen to escape into the air. A disadvantage of this method is that hydrogen is not available to reform into the electrolyte during recharging. This problem is solved by adding water to the electrolyte, such as in an automobile battery. A second method is to use material that is rich in oxygen, such as manganese dioxide, which supplies free oxygen to combine with the hydrogen and form water.
A third method is to use a material that will absorb the hydrogen, such as calcium. The calcium releases hydrogen during the charging process. All three methods remove enough hydrogen so that the cell is practically free from polarization.
LOCAL ACTION
When the external circuit is removed, the current ceases to flow, and, theoretically, all chemical action within the cell stops. However, commercial zinc contains many impurities, such as iron, carbon, lead, and arsenic. These impurities form many small electrical cells within the zinc electrode in which current flows between the zinc and its impurities. Thus, the chemical action continues even though the cell itself is not connected to a load.
Local action may be prevented by using pure zinc (which is not practical), by coating the zinc with mercury, or by adding a small percentage of mercury to the zinc during the manufacturing process. The treatment of the zinc with mercury is called amalgamating (mixing) the zinc. Since mercury is many times heavier than an equal volume of water, small particles of impurities weighing less than mercury will float to the surface of the mercury. The removal of these impurities from the zinc prevents local action. The mercury is not readily acted upon by the acid. When the cell is delivering current to a load, the mercury continues to act on the impurities in the zinc. This causes the impurities to leave the surface of the zinc electrode and float to the surface of the mercury. This process greatly increases the storage life of the cell.
What is the mechanical advantage of the inclined plane below?
a) 2.6
b) 0.8
c) 2.4
d) 0.6
Answers
Answer;
2.6
Explanation;
Formular for mechanical advantage is length of the slope divided by the height of the inclined plane.[tex]1.85 \div 0.72 = 2.56[/tex]Approximately 2.6What are the factors that affect the size of an impact crater?
Answers
Answer:
The following factors could be responsible for size of an Impact Crater:
Geography of the region where it impacted.Size of the Impactor Velocity of the ImpactorHope it helps!<3
19. What energy transformation occurs in a battery?
A. chemical energy to thermal energy
C. electric energy to chemical energy
B. chemical energy to electric energy
D. thermal energy to chemical energy
Answers
i think correct answer is b
Answer:
B.chemical energy changes to electric energy.Explanation:
I hope l helped you. ❤❤if gravity on the earth increased, what affect would it have on the moon
Answers
Answer:
If gravity on Earth is increased, this gravitational tugging would have influenced the moon's rotation rate. If it was spinning more than once per orbit, Earth would pull at a slight angle against the moon's direction of rotation, slowing its spin. If the moon was spinning less than once per orbit, Earth would have pulled the other way, speeding its rotation.
A waterbed has a force of 1300N on the floor. It exerts 347 Pa of pressure. What is the area of the waterbed?
Answers
Answer:
Pressure = Force/Area
347 = 1300/Area
Area = 1300/347
area= 3.47m2
Answer:
I hope the above pic will help you
I will always help you understanding your assingments have a great day
#Captainpower
Is solar power and solar energy the same thing ?
Answers
Answer:
yes I think
Explanation:
Solar energy systems refer to any technology that converts the sun's energy into another form of energy, such as heat or electricity. ... Solar power is a a subset of solar energy, a more narrow term that typically refers to the conversion of the sun's rays to electricity.
Water can form large dewdrops in nature how would droplets made of vegetable oil instead of water be different
Answers
Answer:d
Explanation: oil would form droplets but only tiny ones because it’s surface tension is lower than that of water
Both water and vegetable oil would made droplets but Oil would form only very tiny droplets because its surface tension is lower than that of water.
What is surface tension?Surface tension is the propensity for liquid surfaces that are at rest to condense into the smallest surface area. Razor blades and insects (like water striders), which have a higher density than water, can float on the surface of the water without even becoming partially buried because to surface tension.
Surface tension at liquid-air contacts originates from the liquid molecules' stronger attraction to one another due to cohesion than to the air molecules (due to adhesion).
As the surface tension of the oil is lower than that of water, it forms droplets will smaller size.
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two spheres A and B are projected off the edge of a 1.0 m high table with the same horizontal velocity . sphere A has a mass of 20.g and sphere B has a mass of 10.g.
If both spheres leave the edge of the table at the same instant, sphere A will land
a. at some time after sphere B.
b. at the same time as sphere B.
c. at some time before sphere B.
d. There is not enough information to decide.
Answers
Answer:
c. because A will land first becuase its heavier :)
Explanation:
What is the turning effect of a force?
Answers
A force may cause an object to turn about a pivot. The turning effect of a force is called the moment of the force. Moments act about a pivot in a clockwise or anticlockwise direction.
Answer:
A force may cause an object to turn about a pivot. The turning effect of a force is called the moment of the force. Moments act about a pivot in a clockwise or anticlockwise direction.
Explanation:
What is the frequency of a wave with a Wavelength of 200 cm?
Answers
Explanation:
wavelength =200cm=2m
frequency is reciprocal of wavelength
f=1/2
f=0.5Hz or 1/s
The frequency of the wave with a Wavelength of 200 cm should be considered as the f=0.5Hz or 1/s.
Calculation of the frequency:Since the wavelength is 200 cm or 2m
Also we know that
frequency is reciprocal of wavelength
So,
f=1/2
f=0.5Hz
Hence, The frequency of the wave with a Wavelength of 200 cm should be considered as the f=0.5Hz or 1/s.
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Examples of ohm law and conductor resistance :
So I need help with these things, I did 2 examples but with these 3 I have problems.
I appreciate alot if anyone can handle this
1.Calculate the resistance of a Cu 2-wire line of total length for 1 line of 500m, if it has a cross section of 6mm2.
3.Calculate the voltage drop across the resistor R = 1.2 kΩ when a current I = 125 mA flows through it
2.Calculate the current flowing through the resistor R = 47 Ω if the source has a voltage U = 24 V.
I"m attaching also Microsoft Word file.
Thanks in advance!
-Mathew
Answers
Answer:
see attached file
Explanation:
an electric iron draws a current of 5a when connected to a 250v supply. calculate the energy used buy the iron if it's used for 10 minutes
Answers
Answer:
The energy used by the iron is 0.2083 KWH.
Explanation:
Electric Energy
The energy consumed by an electrical appliance is given by:
E = P.t
Where:
P = Power consumed
t = Time the appliance is connected to the power supply
The power can be calculated as a function of the voltage V and the current I:
P = V.I
Therefore, the energy is:
E = V.I.t
The electric iron draws a current of I=5 A when connected to a V=250 V supply for t=10 minutes. The time must be expressed in hours, thus t=10/60=0.167 hours.
Thus, the energy is:
E = 250 V * 5 A * 0.167 H
E = 208.33 WH
Converting to KWH:
E = 208.33/1000 = 0.2083 KWH
The energy used by the iron is 0.2083 KWH
1.
(01.04 MC)
Subtracting cellular respiration from gross primary productivity is the calculation for (3 points)
normalized difference vegetation index
secondary productivity
principle productivity
net primary productivity
2.
(01.04 MC)
Which of the following describes the calculation for net primary productivity? (3 points)
Adding primary and secondary productivity
Subtracting macronutrients from micronutrients
Multiplying gross primary productivity by cellular respiration
Subtracting cellular respiration from gross primary productivity
3.
(01.04 LC)
Slow conversion of solar energy indicates high primary productivity in an ecosystem. (3 points)
False
True
4.
(01.04 MC)
Which of the following is true of cellular respiration but not of photosynthesis? (3 points)
Cellular respiration releases oxygen gas as a product.
Cellular respiration releases energy from glucose.
Cellular respiration requires carbon dioxide and water as reactants.
Cellular respiration is a process in which glucose is formed.
5.
(01.04 LC)
What energy transfer is occurring when a plant uses energy from the sun to make sugar in fruit? (3 points)
Radiant energy is converted to stored chemical energy.
Radiant energy is converted to nuclear energy.
Thermal energy is converted to stored chemical energy.
Thermal energy is converted to nuclear energy.
6.
(01.04 MC)
Which of the following is a result of lack of visible light at deeper levels in the ocean? (3 points)
Red sea organisms would be highly visible to predators in mid-ocean depths.
Producers deep in the ocean have adaptive mechanisms to conduct photosynthesis with less light.
Productivity does not exist in deep sea environments.
Consumers engage is cellular respiration at rates substantially higher than surface consumers.
7.
(01.04 MC)
Which of the following is true of photosynthesis but not of cellular respiration? (3 points)
Photosynthesis is a process in which glucose is broken down.
Photosynthesis occurs in all organisms.
Photosynthesis releases oxygen gas as a product.
Photosynthesis requires glucose as a reactant.
Answers
Answer: net primary productivity
Explanation: i just took my test and this was correct!
2. Using Graph 2, calculate the net force experienced by the particle between 4 and 6 seconds. The
particle has a mass of 0.25 kg.
A +5.0 N
B. +0.5 N
C. -0.5 N
D. -2.0 N
Answers
Using Newtons Second Law:
F = m×a
F = (0.25 kg)(-2 m/s²)
F = -0.5 N
The correct option is C. A pendulum of length l = 9.8 m hangs in equilibrium and is then given velocity
v
=0.2
m/s at its lowest point. What is the amplitude of the subsequent oscillation?
Answers
Answer:
the amplitude of the sequence oscillation=
ASO = length × velocity
= 9.8 × 0.2 = 19.6
ASO = 19.6
Select all the correct answers.
Which statements are true?
A farsighted person's cornea and lens refract light too much.
A nearsighted person's cornea and lens do not refract light enough.
A person whose eyes are blue has irises that reflect blue light.
Even people with perfectly working eyes have a blind spot in each eye.
A lens with cataracts absorbs or scatters light that it should refract.
Answers
Answer:
e
Explanation:
Answer: E B
Explanation:
10) The coil of transformer is coated by enamel why
Answers
Answer:
Enamel is used to coat the wires, it is the thinnest possible insulator. The coils are made up of large number of turns and enamel makes it possible to cram a lot of wires (coils) in much smaller space.
A 0.9 kg ball attached to a cord is whirled in a vertical circle of radius 2.5 m. Find the minimum speed needed at the top of the circle so that the cord remains taut and the ball’s path remains circular.
Answers
Answer:
The minimum speed needed at the top of the circle so that the cord remains tensioned and the ball's path remains circular is approximately is 9.903 meters per second.
Explanation:
By the Principle of Energy Conservation we understand that the minimum speed needed by the ball is that speed such that maximum height reached is equal to the diameter of the vertical circle, that is:
[tex]K =U_{g}[/tex] (1)
Where:
[tex]K[/tex] - Translational kinetic energy, measured in joules.
[tex]U_{g}[/tex] - Gravitational potential energy, measured in joules.
By definitions of translational kinetic and gravitational potential energies, we expand the equation above and clear the initial speed of the ball:
[tex]\frac{1}{2}\cdot m \cdot v^{2} = m\cdot g\cdot h[/tex]
[tex]v = \sqrt{2\cdot g\cdot h}[/tex] (2)
Where:
[tex]m[/tex] - Mass, measured in kilograms.
[tex]v[/tex] - Initial speed, measured in meters per second.
[tex]g[/tex] - Gravitational acceleration, measured in meters per square second.
[tex]h[/tex] - Maximum height of the ball, measured in meters.
If we know that [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]h = 5\,m[/tex], then the initial speed of the ball is:
[tex]v = \sqrt{2\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (5\,m)}[/tex]
[tex]v\approx 9.903\,\frac{m}{s}[/tex]
The minimum speed needed at the top of the circle so that the cord remains tensioned and the ball's path remains circular is approximately is 9.903 meters per second.
What is the centripetal force necessary to keep a 0.4 kg object rotating in a circular path
of radius 3m?
Answers
Answer:
ertdhrsg
Explanation:
gesrgsg
3. A cart (m= 10.0 kg) is currently traveling with a velocity of 3.0 m/s. The cart then gains speed,
achieving a new velocity of 7.0 m/s after 8.0 seconds. Calculate the magnitude of the net force acting
on the cart.
A 0.0 N
B. 1.25 N
C. 5.0 N
D. 80N
Answers
First we calculate the acceleration of the cart:
a = (v₂ - v₁) / (t)
a = (7 m/s - 3 m/s) / (8 s)
a = 4 m/s / 8 s
a = 0.5 m/s²
Using the Newtons Second Law:
F = m×a
F = (10 kg)(0.5 m/s²)
F = 5 N
The correct option is CWho won Miami Dolphins or Las Vegas raiders
Answers
Answer:
miami dolphins.
Explanation:
......
Answer:
miami :(
Explanation:
help please Derive an equation
Ta=1.44T1/2
Answers
Explanation:
To derive an equation you must indicate the variable you want to solve for.
Here we have tension of an object A and Tension 1.
Two variables or unknown are given hence we cannot derive any other equations.