Henry mixed salt and water together in a cup until he observed a clear solution. He measured the mass of the solution. Then he placed the cup outside for several sunny days during the summer. After a week, he observed that only solid salt remained in the cup and the mass had decreased. Henry concluded that a physical and chemical change occurred in this investigation.
Which statements correctly defend or dispute his conclusion?
He is correct. Dissolving salt in water is a physical change, but evaporating the water is a chemical change. Formation of a solid is evidence that a chemical change occurred.
He is correct. Evaporation is a physical change, but dissolving salt in water is a chemical change. The change in mass is evidence that a chemical change occurred.
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
He is incorrect. Dissolving salt in water and evaporation of the water are both chemical
Answer:
He is incorrect. Dissolving salt in water and evaporation of the water are both physical changes. The reappearance of salt is evidence that the change was reversible by a physical change, so it could not be a chemical change.
Answer:c
Explanation:
Calculate the momentum of a 4,800 kg car with a velocity of 25 m/s.
Answer:
p = 120000 kg · m/s
Explanation:
p = mv
p=momentum
m=mass
v=velocity
p = (4800)(25)
p= 120000 kg · m/s
Answer:
[tex]momentum = mass \times velocity \\ = 4800 \times 25 \\ = 120000 \: kgm {s}^{ - 1} [/tex]
A resistor of 500Ω and one of 2000Ω are placed in series with a 60V supply. What will be the reading on a voltmeter of internal resistance 2000Ω when placed across (i) 500Ω resistor and (ii) 2000Ω resistor?
Answer: 10 V, 40 V
Explanation:
Given
Resistors are [tex]500\Omega[/tex] and [tex]2000\Omega[/tex]
Power supply [tex]V=60\ V[/tex]
Voltmeter internal resistance [tex]r=2000\ \Omega[/tex]
When it connected around [tex]500\Omega[/tex] resistance, effective resistance becomes
[tex]\Rightarrow \dfrac{1}{R}=\dfrac{1}{500}+\dfrac{1}{2000}\\\\\Rightarrow R=\dfrac{2000}{5}\\\\\Rightarrow R=400\ \Omega[/tex]
Total resistance in series [tex]R_{net}=2400\ \Omega[/tex]
Current in circuit
[tex]I=\dfrac{60}{2400}=\dfrac{1}{40}\ A[/tex]
Voltage around [tex]500\Omega[/tex] resistance is
[tex]V=\dfrac{1}{40}\times 400\\\\V=10\ V[/tex]
(B) when voltmeter is connected around [tex]2000\Omega[/tex] resistor
Net resistance around it
[tex]\Rightarrow \dfrac{1}{R}=\dfrac{1}{2000}+\dfrac{1}{2000}\\\\\Rightarrow R=1000\ \Omega[/tex]
Total resistance [tex]R_{net}=1500\ \Omega[/tex]
Current in circuit
[tex]I=\dfrac{60}{1500}=\dfrac{1}{25}\ A[/tex]
Voltage around [tex]2000\Omega[/tex] resistor
[tex]V=\dfrac{1}{25}\times 1000\\\\V=40\ V[/tex]
Find new resistance of wire if it is stretched to twice its
original length. Original resistance was 20 ohm. Also how its
resistivity will change
Answer:
Original Length = L1
Stretched length =L2
From
R = pl/A
R=Resistance
p=Resistivity
A=Cross-sectional Area
l= length of wire
We can see that Resistance is directly Proportional to Length... Meaning that Resistance Increases also as Length increases.
R1/L1 = R2/L2
From the question... The key to note is this sentence
"The Stretched length is TWICE the Original Length"
Meaning
L2 = 2L1 (So replace L2 as 2L1 when solving)
R1=20ohms
Let R2 = k
Applying the formula
20/L1 = k/2L1
kL1 = 20x 2 L1
KL1 = 40L1
L1 cancels on both sides
k=40ohms.
So As the length doubled... The Resistance did too
from 20ohms to 40ohms
A 91.5 kg football player running
east at 2.73 m/s tackles a 63.5 kg
player running west at 3.09 m/s.
What is their velocity afterward?
Answer:
I'm pretty sure the velocity is 2.88 m/s
Explanation:
hope this is right good luck
Answer:
0.348
Explanation:
Acellus
Which of the following physical quantity is having same SI units?
a) Speed and average speed
b) Speed and velocity
c) Speed and average velocity
d) All the above
Answer:
d) All the above
Explanation:
Speed SI unit is metre per second.Velocity SI unit is metre per second.Average speed SI unit is metre per second.Average velocity SI unit is metre per second.Therefore, as all of the physical quantities have the same SI units, the answer is d) all of the above.
Air pollution is an example of a. The underground economy. B. An external shock. C. A nonmarket activity. D. A negative externality.
Answer:
D. A negative externality.
Explanation:
Particulate pollution is a form of pollution that is responsible for the degradation of the environment.
Particulate matter is also referred to as particle pollution or atmospheric aerosol particles and it can be defined as a complex microscopic mixture of liquid droplets and solid particles that are suspended in air.
An externality is typically an unwarranted cost or benefit by a manufacturer or producer of goods and services that affects a third party.
In Economics, an externality could either be positive or negative depending on its effect on a third party.
A negative externality arises when the production or consumption of a finished product or service has negative impact (cost) on a third party.
In conclusion, air pollution is an example of a negative externality because it causes harm to a third party.
1. 10. waves break on the beach in 2.0 min. What is the frequency in hertz of these waves (cycles per
second)? What is the time between successive waves, in seconds?
Answer:
there it is fella tried o. ma own consciousness
Si un automóvil logra una potencia util promedio de 250kw y se sabe que tiene un rendimiento energético del 25%. ¿Cuanta energia total consume en 1 min? Exprese el resultado en kj
Answer:
W = 3.75 kJ
Explanation:
Power is defined by the relational
P = W / t
W = P t
the yield is 25% = 0.25
W = 0.25 Wo
W = 0.25 250 60
W = 3750 J
W = 3.75 kJ
The atomic mass of calcium is 40.08. What is the mass of 6.02 × 1023 atoms of calcium?
Answer:
It is 40.08 g
Explanation:
[tex]6.02 \times 10 {}^{23} \: atoms = 1 \: mole = 40.08 \: g[/tex]
6. Which of the following graphs correctly demonstrates the relationship between the
electromagnetic force and distance between charges?
Answer:
But where are the graphs
Coulomb's Law describes the relationship between electromagnetic force and the distance between charges.
What is the relationship between electromagnetic force and the distance between charges?The relationship between electromagnetic force and the distance between charges is described by Coulomb's Law, which states that the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Mathematically, Coulomb's Law is expressed as:
F = k (q₁x q₂) / r²
where F is the electromagnetic force, q1 and q2 are the charges, r is the distance between the charges, and k is the Coulomb constant.
This means that as the distance between two charges increases, the force between them decreases, and as the distance decreases, the force increases. The relationship between force and distance is inverse square, which means that the force decreases rapidly as the distance increases.
To know more about electric charges follow
https://brainly.com/question/874116
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Incident beam
Which order is the brightest?
Answer:
mark me as the brainliest plss
how can you reduce output voltage to 6v in transformers if the input voltage is 240v
Answer:
[tex]N_P = 40\ N_S[/tex]
To reduce the output voltage to 6v in transformers if the input voltage is 240v, we need to have 40 times as many turns in the primary coil as there are in the secondary coil.
Explanation:
The change in voltage of a transformer depends upon the turns ratio of the transformer between secondary and primary coil. Following formula can be used to determine the turns ratio in this case:
[tex]\frac{N_P}{N_S} = \frac{V_P}{V_S} \\\\[/tex]
where,
[tex]N_P[/tex] = No. of turns in the primary coil
[tex]N_S[/tex] = No. of turns in the secondary coil
[tex]V_P[/tex] = voltage in the primary coil = 240 V
[tex]V_S[/tex] = voltage in the secondary coil = 6 V
Therefore,
[tex]\frac{N_P}{N_S} = \frac{240\ V}{6\ V} \\\\N_P = 40\ N_S[/tex]
To reduce the output voltage to 6v in transformers if the input voltage is 240v, we need to have 40 times as many turns in the primary coil as there are in the secondary coil.
When a car velocity is negative and its acceleration is negative, what is happening to the cars motion?
Answer:
The car is speeding up in a negative direction.
Explanation:
Select all the correct answers. Which statements about potential energy are true?
Answer: The statement gaining potential energy is always associated with a force field, is true about potential energy.
Explanation:
The energy acquired by an object due to its position is called potential energy.
Basically, a force field exerts a force that gives rise to potential energy of an object. For example, gravity, spring force etc.
This means that gaining potential energy is always associated with a force field.
A change in position does not always means that an object gains potential energy. For example, a spring will have more potential energy when it is compressed or stretched.
Hence, change in position of an object not necessarily means always gain in potential energy.
There are two types of potential energy that is, gravitational potential energy and elastic potential energy.
Thus, we can conclude that the statement gaining potential energy is always associated with a force field, is true about potential energy.
Answer:
Explanation:
The first one and the last one are the correct answer.
For a specific volume of 0.2 m3/kg, find the quality of steam if the absolute pressure is (a) 40 kPa and (b) 630 kPa. What is the temperature of each case?
Answer:
[tex]x=0.0498[/tex]
[tex]x'=0.659[/tex]
Explanation:
Specific Volume [tex]V=0.2m_3/kg[/tex]
Absolute Pressure (a) [tex]P_a= 40kpa[/tex]
Giving
[tex]T_a=75.87[/tex]
[tex]v_f=1.265*10^{-3}m^3/kg[/tex]
[tex]v_g=3.993m^3/kg[/tex]
(b) [tex]P_a= 630kpa[/tex]
Giving
[tex]T_b=160.13C[/tex]
[tex]v_f'=1.10282*10^{-3} m^3/kg[/tex]
[tex]v_g'=0.30286 m^3/kg[/tex]
(a)
Generally the equation for quality of Steam X is mathematically given by
[tex]x=\frac{v-v_f}{v_g-v_f}[/tex]
[tex]x=\frac{0.2-1.0265*10^{-3}}{3.993-1.0265*10^{-3}}[/tex]
[tex]x=0.0498[/tex]
(b)
Generally the equation for quality of Steam X is mathematically given by
[tex]x'=\frac{v-v_f'}{v_g'-v_f'}[/tex]
[tex]x'=\frac{0.2-1.10*10^{-3}}{3.30-1.1*10^{-3}}[/tex]
[tex]x'=0.659[/tex]
Sound travels slowest through gases _____________________. Group of answer choices because the molecules of gas are close together because gases are air because the molecules of gas are far apart because gases have the lowest temperature
6. A ball rolled 125 m from the top of a hill to the bottom of a hill. How long
did it take for the ball to roll if the average velocity was 5m/s? *
what is the frequency range of Audible sound
Answer:20Hz to 20000Hz
Explanation:
Humans can detect sounds in a frequency range from about 20 Hz to 20 kHz.
Ponds and lakes are part of marine ecosystem.
True or false ?
Answer:
True
Explanation:
because they can hold marine organism inside
physics
please help
its physic based on the law of movement
Explanation:
4) The net torque on the on the meter stick is equal to zero in order to have no rotation.
[tex]\tau_{1} = \tau_{2}[/tex]
[tex]F_{1}d_{1} = F_{2}d_{2}[/tex]
[tex](8 \:N)(0.3\: m) = F_{2}(0.1 \:m)[/tex]
[tex]F_{2} = \frac{(8 \:N)(0.3 \:m)}{(0.1 \:m)} = 24 \:N[/tex]
5) We are going the same equations in #4 here.
[tex]F_{1}d_{1} = F_{2}d_{2}[/tex]
[tex](500 \:N)(2.4 \:m) = F_{2}(3.0 \:m)[/tex]
[tex]F_{2} = \frac{(500 \:N)(2.4 \:m)}{(3.0 \:m)} = 400 \:N[/tex]
A sound wave has a frequency of 192 Hz and travels the length of a football field at a speed of 338.5 m/s. what is the wavelength of the wave?
Explanation:
everything can be found in the picture
A scientist is examining an unknown solid. Which procedure would most likely help determine a chemical property of the substance?
heating it to find the temperature at which it melts
exposing it to a flame to see if it catches on fire
hitting it with a hammer to determine if it breaks or bends
placing it in water to find out whether or not it dissolves
Answer:
hitting it with a hammer to determine if it breaks or bends
Answer:
exposing it to a flame to see if it catches on fire
Explanation:
A chemical property is when the matter changes into a different substance. This is true when you expose it to a flame because if a substance is burned, it will change into a new substance. All the other options are examples of physical changes.
-I also took the quiz and got 100%
Hope this helps!
what is unit of pressure?why is it called a derived unit ? give reasons
Answer:
Unit of pressure is pascal (Pa)
The SI-derived unit of measurement for pressure. The pascal is one newton (an SI-derived unit itself) per square meter.
Which property of the coating on fiber-optic strands makes light visible only at the ends of the strands?
reflectivity
absorbency
transparency
translucency
The answer is A, Hope this helps and sorry for being late :)
A book with a mass of 2 kg sits on top of a book shelf at a height of 3 m. How much potential energy does the book have
Answer:
Answer is 98 joules
Explanation:
P. E=2*9.8*3=98
S.i unit of potential energy ⚡ is joules
So answer is 98 joules
I need help pleaseee
Answer:
a refraction
b reflection
creflection
d refraction
brainliest plzz
what is matter explain verifly
Answer:
Matter is a substance that has inertia and occupies physical space. According to modern physics, matter consists of various types of particles, each with mass and size.Matter can exist in several states, also called phases. The three most common states are known as solid, liquid and gas.Matter is the Stuff Around You or Atoms and compounds are all made of very small parts of matter. Those atoms go on to build the things you see and touch every day. Matter is defined as anything that has mass and takes up space (it has volume).Solid ice, water and steam are few examples of matter touched in everyday life. Subatomic particles are also considered as matter.
Answer:
Matter is everything around you. Atoms and compounds are all made of very small parts of matter. Those atoms go on to build the things you see and touch every day. Matter is defined as anything that has mass and takes up space (it has volume).
hope it helps...
When a shopping cart rolls into a parked car on the street, It hits the car with a force of 220 newtons. The shopping cart experiences a force from the car that is how many newtons?
Answer:
220 N
Explanation:
When a shopping cart rolls into a parked car on the street, it hits the car with a force of 220 newtons.
We need to find the force the shopping cart experiences from the car.
We know that, Newton's third law of motion states that for every action there is an equal and opposite reaction.
Hence, the shopping cart experiences a force of 220 N from the car.
A hippopotamus laying on the rock exerts 10,000 N on the rock. The rock has a mass of
2 tons. How much work is being done? Be sure to show your work.
Answer:
Explanation:
If the hippo is laying on the rock, I'm assuming that there is no movement going on at all, in either the hippo or the rock. If no movement occurs, there is no work being done.
