A swimmer who can swim in still water at a speed of 4km/h is swimming in a river. the river flows at a speed of 3km/h. calculate the speed of the swimmer relative to the river bank when she swims:- 1. downstream 2.upstream​

Answers

Answer 1

Explanation:

Downstream: you just sum the magnitude of the velocity vectors:

3km/h + 4km/h = 7km/h

Upstream: difference of the magnitudes of the velocity vectors, in absolute value:

|3km/h - 4km/h| = 1km/h


Related Questions

Three people are trying to move a box. Which set of forces will result in a net
force on the box of 20 N to the left?

Answers

Answer: push force gravity tension and reverse force

Explanation: sense they are pushing the box there is a push force gravity because this is likely on earth tension because it is the reverse of gravity and the reverse force because you have to have the reverse of push

SOMEONE PLEASE HELP MEEEEEEE

Answers

Answer:

The movement of Tectonic plates.

Explanation:

An object in free fall has a velocity of 5m/s in the upward direction. What is the instantaneous velocity of the object one second later?

Answers

Answer:

Explanation:

Near the earth's surface where gravity is approximately 10 m/s² downward

v = u + at

v = 5 + (-10)(1) = -5 m/s

so it has the same speed but in the opposite (downward) direction.

The instantaneous velocity of the object is -4.8 m/s and is directed downwards.

What is meant by instantaneous velocity ?

Instantaneous velocity is defined as the rate of change of position for a given interval of time. And it also represents the direction.

Here,

The object is freely falling.

So, the acceleration of the object is the acceleration due to gravity.

a = g = 9.8 m/s²

Initial velocity of the object, u = 5 m/s  (upward velocity)

Time given, t = 1

Using the first equation of motion,

v = u + at

v = 5 + (-9.8) x 1  

( negative sign is due to it is directed downwards which is opposite to u)

v = -4.8 m/s

That means the instantaneous velocity is directed downwards.

Hence,

The instantaneous velocity of the object is -4.8 m/s and is directed downwards.

To learn more about instantaneous velocity, click:

https://brainly.com/question/2273637

#SPJ3

Where do hyperbolic comets originate?
A. the Oort cloud
B. the asteroid belt
C. the Kuiper belt
D. interstellar space

Answers

Answer:A.the Oort cloud

Explanation:

Answer:

try answer A..the Ootor cloud

How is the çhocolate shell on the outside of the bar different from the ice cream on the inside?

Answers

Answer:

Cake Crunch (Enriched Wheat Flour [Bleached Flour, Niacin, Reduced Iron, Thiamine Mononitrate, Riboflavin, Folic Acid]), Sugar, Vegetable Shortening [Partially Hydrogenated Soybean and Cottonseed Oil], Salt, Sodium Bicarbonate, Artificial Flavor, Soy Lecithin, Soybean Oil, Coconut Oil, Sugar, Chocolate Liquor, ...

Make a generalization about Earth's magnetic field and its properties. In not more than 10 sentences.​

Answers

Answer:

Earth's magnetic field (and the surface magnetic field) is approximately a magnetic dipole, with the magnetic field S pole near the Earth's geographic north pole (see Magnetic North Pole) and the other magnetic field N pole near the Earth's geographic south pole (see Magnetic South Pole). This makes the compass usable for navigation. The cause of the field can be explained by dynamo theory. A magnetic field extends infinitely, though it weakens with distance from its source. The Earth's magnetic field, also called the geomagnetic field, which effectively extends several tens of thousands of kilometres into space, forms the Earth's magnetosphere. A paleomagnetic study of Australian red dacite and pillow basalt has estimated the magnetic field to be at least 3.5 billion years old

Need help ASAP, 1 MC

Answers

Answer:

The first one is the only one that is true all the time

Explanation:

The second one may be true if friction is high enough.

The other three are false all the time

8th grade science !
can someone help me with trying to understand this question for my homework especially how to understand the graph and use that for my evidence and help me give an idea of how should I write the evidence and reasoning?​

Answers

Answer:

for reasoning you could put -> the line is at the top at the left handed sided of the chart (also the beginning) slopes down towards the very bottom right handed side of the chart, symbolising less force as distance goes.

if it takes a track runner 2.16 seconds to reach a speed of 5.31 m/s from the start of a race, what is the runners acceleration?

Answers

Answer:

Explanation:

Answer:

Explanation:

Question: Self-test 3.12 Calculate the change in G for ice at -10°C, with density 917 kg mº, when the pressure is increased from 1.0 bar to 2.0 bar.​

Answers

The change in the Gibb's free energy per mole (G) is 1.96 J.

The given parameters:

Density of the ice, ρ = 917 kg/m³Initial pressure, P₁ = 1.0 barFinal pressure, P₂ = 2.0 barTemperature, T = - 10 CMass of water = 18 g

The change in the Gibb's free energy per mole (G) is calculated as follows;

[tex]\Delta G = V(P_2-P_1) \\\\[/tex]

where;

V is the volume of the ice

[tex]Density = \frac{Mass}{Volume} \\\\Volume = \frac{Mass}{Density} \\\\Volume = \frac{18 \times 10^{-3} \ kg}{917 \ m^3} \\\\Volume = 1.96 \times 10^{-5} \ m^3\\\\Volume = 1.96 \times 10^{-5} \ m^3 \times \frac{1000 \ L}{m^3} \\\\Volume = 0.0196 \ L[/tex]

Change in pressure;

[tex]P_2 - P_1 = 2.0 \ bar \ - \ 1.0 \ bar = 1.0 \ bar = 0.987 \ atm[/tex]

The change in the Gibb's free energy per mole (G);

[tex]\Delta G= V(P_2-P_1)\\\\\Delta G = 0.0196\ L \times 0.987\ atm \\\\\Delta G = 0.0193 \ L.atm\\\\1 \ L.atm = 101.325 \ J\\\\\Delta G = 0.0193 \ L.atm \times \frac{101.325 \ J}{1 \ L.atm} \\\\\Delta G = 1.96 \ J[/tex]

Thus, the change in the Gibb's free energy per mole (G) is 1.96 J.

Learn more about Gibb's free energy here: https://brainly.com/question/10012881


Two Blocks are connected by a massless rope over a massless,
frictionless pulley, as shown in the figure. The mass of block 2
is m2 = 10.1 kg, and the coefficient of kinetic friction
between block 2 and the incline is Mk = 0.200. The angle 0 of
the incline is 27.5º. If block 2 is moving up the incline at
constant speed, what is the mass mi of block 1?

Answers

The mass of block 1 will be 1.99 kg.The tension force is applied along the whole length of the wire, pulling energy equally on both ends.

What is tension force?

The tension force is described as the force transferred through a rope, string, or wire as it is pulled by opposing forces.

Given that,

Mass of block 1=? kg

The coefficient of the kinetic friction,μ=0.200

Now consider the weight component in the uphill direction.The weight is found as;

[tex]\rm W=m_1gsin \theta[/tex]

The force is balanced in the vertical direction as;

[tex]\rm T=F_f-W[/tex]

When the force of friction is;

[tex]\rm F_F=\mu_k N[/tex]

[tex]\rm F_f=(m_1 gcos \theta)[/tex]

Substitute the value in the vertical balanced equation;

[tex]\rm T=m_1gsin(27.5)^0-\mu_kmgcos27.5^0[/tex]

[tex]\rm T-m_2g=0\\\\T=m_2g[/tex]

[tex]\rm (10.1) g=m_1g(0.699-0.2 \times(-0.714) ) \\\\ (10.1) g=m_1g (0.699+0.1428) \\\\\ (10.1) g= m_1 \times 0.8418 \\\\ m_1 =11.99 \ kg[/tex]

Hence the mass of block 1 will be 1.99 kg.

To learn more about the tension force refer to the link;

https://brainly.com/question/2287912

#SPJ2

Who actually asked Abraham to sacrifice his son?

Answers

Answer:

Allah asked Abraham(Ibrahim)

A 4.0-mF capacitor initially charged to 50 V and 6.0-mF capacitor charged to 30 V are connected to each other with the positive plate of each connected to the negative plate of the other. what is the final charge of the 6.0-mF capacitor?

a. 20 mC
b. 8.0 mC
c. 10 mC
d. 12 mC
e. 230 mC

Answers

[tex]\huge\color{pink}\boxed{\colorbox{black}{Answer ☘}}[/tex]

12 mC

Explanation:

We are given that...

[tex]C_{1} = 4mF \\ V_{1} = 50v \\ C_{2} = 6mF \\ V_{2} = 30v \\ \\ we've \: to \: find \: the \: final \: charge \: on \: the \: 6mF \\capacitor \:- \\ \\ we \: know \: that ,\: \\ Q = CV \\ \\ using \: the \: formula \: \\ Q_{1} = 4 \times 50 = 200mC \\ Q_{2} = 6 \times 30 = 180mC \\ \\ total \: charge , \: Q_{1} - Q_{2} = 200 - 180 = 20mC \\ \\ let \: V \: be \: the \: final \: potential \: \\ 4V + 6V = 20mC\\ 10V = 20mC \\ V = \frac{20}{10} = 2V \\ final \: charge \: Q = CV = 6 \times 2 = 12mC[/tex]

therefore,

σptíσn ( d ) íѕ cσrrєct!

hope helpful~

~Be Brainly!

Hydrochloric acid and sodium hydroxide react to produce water and sodium chloride in endothermic reaction. Which statement must be true of the reaction?

A. more bond energy is absorbed on the reactants side than is released on the products side.

B. The energy of each bond in water and sodium chloride is greater than the energy of each bond in hydrochloric acid and sodium hydroxide

C. The bond energy used to break the bonds in hydrochloric acid in the sodium hydroxide is less than the energy released to from the bonds in water and sodium chloride.

D. The total energy of wster and sodium chloride is greater than the total bond energy of hydrochloric acid and sodium hydroxide. ​

Answers

In the endothermic reaction, the total energy of water and sodium chloride is greater than the total bond energy of hydrochloric acid and sodium hydroxide.

Endothermic reactions are reactions in which heat energy is absorbed during the reaction. The formation of products by the reactants requires addition of heat because the energy required to form the bond in the products is greater than the energy released when reactant bond are broken.

Thus, in an endothermic reaction, the total bond energy of the products are greater than the bond energy of the reactants.

The properties of endothermic reactions include:

Heat is absorbed by the system from the surroundings The entropy of the surrounding decreases (ΔS <0) Enthalpy change (ΔH) is positive

Examples of endothermic reactions include;

Cooking of foodDissolution of ammonium chloride in water

The reaction between acids and bases to form salt and water known as neutralization reactions are usually exothermic in nature.

However, if a given reaction between hydrochloric acid and sodium hydroxide to produce water and sodium chloride is endothermic as in the question, the total energy of water and sodium chloride is greater than the total bond energy of hydrochloric acid and sodium hydroxide. ​

Learn more at: https://brainly.com/question/11906094

Learn more at: https://brainly.com/question/6506846

Answer: C.) The total bond energy of water and sodium chloride is greater than the total bond energy of hydrochloric acid and sodium hydroxide.

Hope this helps :)

How many valence electrons do most stable atoms have?

A) one

B) two

C) four

D) eight

Answers

Answer:

D) 8

Explanation:

Due to the octet rule the most stable atoms will have 8 valence electrons.

In three to five sentences, identify the acid, base, conjugate acid, and conjugate base. Use patterns in the periodic table to explain why the substances you identified acted as the acid and the base in this reaction.

Answers

A conjugate acid is formed from the base  by accepting a proton from the acid .

A conjugate base is obtained from the Brownstead - Lowry acid when it looses a proton while the conjugate acid is obtained from the Brownstead - Lowry base when it accepts a proton. In the Brownstead - Lowry sense, acid base reaction involves the loss or gain of a proton.

Consider the hypothetical reaction; AH + :B ⇄ BH + :A. The specie BH is the conjugate acid while the specie  :B is the  Brownstead - Lowry base . The specie :A is the conjugate base while the specie AH is the  Brownstead - Lowry acid.

Learn more about conjugate acid: https://brainly.com/question/10468518

What is the plot of the story the monkey and the crocodile

Answers

Answer:

the plot is about a crocodile who lives in a river.....

Explanation:

It is about a crocodile who lives in a river. He becomes friends with a monkey that lives on a tree on the river bank. Consequently, the monkey shares the fruits of the tree with his friend, the crocodile. Further, the crocodile takes a share for his wife.

Someone please help with this question. From my knowledge the answer I believe to be correct is 4Em but I’m still not so sure. Please explain!
Answer choices:
1/2 Em
Em
2Em
4Em

Answers

Answer:

Explanation:

For an ideal spring over a frictionless horizontal surface, stored energy is only a function of the spring constant k and the distance of compression. The mass of the block doing the compressing is irrelevant

Energy stored in the first example is

Em = ½kd²

Energy stored in the second example is

E₂m = ½k(2d)² = 4(½kd²) = 4Em

So the second situation has four times as much stored spring potential energy as the first situation

4 Em is correct

Good job!

Who did the ram caught in the thicket (Genesis 22:13) represent?

Answers

Answer:

I think the answer is goat

g A 24-gg bullet strikes and becomes embedded in a 1.50-kgkg block of wood placed on a horizontal surface just in front of the gun. Part A If the coefficient of kinetic friction between the block and the surface is 0.23, and the impact drives the block a distance of 9.5 mm before it comes to rest, what was the muzzle speed of the bullet

Answers

The muzzle speed of the bullet before the collision is 415.3 m/s.

The given parameters:

Mass of the bullet, m₁ = 24 gMass of the wood, m₂ = 1.5 kgCoefficient of kinetic friction, μk = 0.23Distance traveled by the block before stopping, d = 9.5 m

Apply the principle of work-energy theorem to determine the final velocity of the block-bullet system;

[tex]F_f \times d = \frac{1}{2} mv^2\\\\\mu_k F_n \times d = \frac{1}{2} mv^2\\\\\mu_ k (m_1 + m_2)g \times d = \frac{1}{2} (m_1 + m_2)v^2\\\\\mu_k g \times d= \frac{1}{2} v^2\\\\2\mu _k gd = v^2\\\\v= \sqrt{2\mu _k gd } \\\\v = \sqrt{2 \times 0.23 \times 9.8 \times 9.5} \\\\v = 6.54 \ m/s[/tex]

Apply the principle of conservation of linear momentum to determine the muzzle speed of the bullet;

[tex]m_1 u_1 \ + \ m_2u_2 = v(m_1 + m_2)\\\\0.024(u_1) \ + \ 1.5(0) = 6.54(0.024 + 1.5)\\\\0.024u_1 = 9.967\\\\u_1 = \frac{9.967}{0.024} \\\\u_1 = 415.3 \ m/s[/tex]

Thus, the muzzle speed of the bullet before the collision is 415.3 m/s.

Learn more about conservation of linear momentum here: https://brainly.com/question/7538238

A dwarf planet has a mass of 0.0045 times that of the Earth and a diameter on average 0.19 times that of the Earth. What is the escape velocity of the dwarf planet? (Type in the numerical answer and unit, e.g. 10m/s)

Answers

The escape velocity of the dwarf planet is 1,721.8 m/s.

The given parameters:

Mass of the dwarf planet, m = 0.0045 MMass of the Earth = 5.98 x 10²⁴ kgDiameter of the planet, d = 0.19 DDiameter of the Earth, D = 12,742 km

The mass of the of the dwarf planet is calculated as follows;

[tex]m = 0.0045 \times 5.98 \times 10^{24} \ kg\\\\m = 2.69\times 10^{22} \ kg[/tex]

The radius of the dwarf planet is calculated as follows;

[tex]r = \frac{0.19 D}{2} \\\\r = \frac{0.19 \times 12, 742, 000}{2} \\\\r = 1,210,490 \ m[/tex]

The escape velocity of the dwarf planet is calculated as follows;

[tex]v _e = \sqrt{\frac{2GM}{r} } \\\\v_e = \sqrt{\frac{2\times 6.67 \times 10^{-11} \times 2.69 \times 10^{22}}{1,210,490}}\\\\v_e = 1,721.8 \ m/s[/tex]

Learn more about escape velocity here: https://brainly.com/question/13726115

When Elements neutral atom contains 5 neutrons 4 electrons and 4 protons

Answers

Answer:

What is the atomic number of an atom that has 5 neutrons and 4 electrons? A neutral atom will have the same number of electrons is does protons. Since it has 4 protons, it must have an atomic number of 4. (That makes it beryllium.)

Explanation:

mark me brainliest please and thank you Ma'aM/Sir

Answer:

4 protons, 5 neutrons, and 4 electrons are there in an atom of beryllium.

1. An airplane flies with an airspeed (speed relative to the air) of 215
km/h. The wind is blowing at 45.0 km/h. Find the velocity of the
plane (relative to the ground) if the plane is pointed straight west and
the wind is:

A. blowing toward the
west (3 points)

B. blowing toward the east (3 points)

C. blowing toward the south (4 points)
(For part C be sure to calculate the angle as well.)

Answers

Answer:

Explanation:

A) 215 + 45.0 = 260 km/h West

B) 215 - 45.0 = 170 km/h West

C) √(215² + 45.0²) = 219.6588... 220 km/h

θ = arctan(45.0/215) = 11.8214... 11.8° S of W

The airplane's ground velocity is westward at 170 km/h regardless of wind direction. The south wind does not affect the plane's westward velocity in component C.

Vector addition will determine each scenario's plane velocity relative to the ground. We'll simplify by assuming a consistent horizontal breeze.

Let's divide the airplane's velocity and wind velocity into westward (negative) and eastward (positive) components.

Data: Plane airspeed = 215 km/h.

45 km/h wind.

A. West wind:

The airplane's westward (negative) ground velocity:

West aeroplane velocity = -215 km/h

-45 km/h west wind.

Find Vg when the wind blows west:

Vg (west) = Aeroplane velocity + Wind velocity (west)

Vg(west) = -215 km/h - (-45 km/h)

Vg (west)=-170 km/h

B. East wind: 2. Westward (negative) aeroplane velocity relative to the ground:

West aeroplane velocity = -215 km/h

Wind velocity (east) = 45 km/h (because the wind is blowing eastward)

Find Vg when the wind blows east:

Vg (west) = Aeroplane velocity (west) + Wind velocity (east).

Vg (west) = -215 + 45 km/h

Vg (west)=-170 km/h

C. Southerly wind: 3. Westward (negative) aeroplane velocity:

West aeroplane velocity = -215 km/h

Wind velocity (south) = 0 km/h (no effect since wind is not moving westward)

Find Vg when the wind blows south:

Vg (west) = Aeroplane velocity (west) + Wind velocity (south).

Vg (west) = -215 + 0 km/h.

Vg (west)=-215 km/h

All resultant velocities are westward and 170 km/h.

Part C's plane's westward velocity is unaffected by the south wind. The plane's ground velocity remains -215 km/h (westward). Since the heading is westward, no angle is needed.

To know more about velocity

https://brainly.com/question/80295

#SPJ2

Please help me answer the following question!

What is the momentum of a 750-kg Volkswagen Beetle when at rest?
Please give the Value and Unit

Answers

Answer:

P = 0

Explanation:

Momentum is defined as the quentity of motion contained in a body. Mathematically, it can be defined as the product of mass and velocity. So, in order to determine the Volkswagen Beetle, at rest, we can use the simple formula, as follows:

where,

P = Momentum of Volkswagen Beetle = ?

m = Mass of Volkswagen Beetle = 750 kg

v = Velocity of Volkswagen Beetle = 0 m/s (since, it is at rest)

Therefore,

P =

What is the name of Fe(NO3)3

Answers

Answer:

Iron(III) nitrate

Explanation:

The motor in a hairdryer is attached to a 3V battery. A current of 0.8A flows through the motor for 3 minutes. Calculate the total charge in this time.

Answers

The total charge in this time is equal to 144 Coulomb.

Given the following data:

Voltage = 3 VoltsCurrent = 0.8 AmperesTime = 3 minutes.

To calculate the total charge in this time:

First of all, we would convert the value of time in minutes to seconds.

Conversion:

1 minute = 60 seconds

3 minutes = 180 seconds

Formula for quantity of charge.

Mathematically, the quantity of charge is given by this formula:

[tex]Q=It[/tex]

Where:

Q is the quantity of charge.I is the current.t is the time measured in seconds.

Substituting the given parameters into the formula, we have;

[tex]Q = 0.8 \times 180[/tex]

Quantity of charge, Q = 144 Coulomb.

Read more on charges here: https://brainly.com/question/4313738

Answer:

960 watts

Explanation:

2. What is the oxidation number of oxygen in most compounds?
A. 6
B.-2
C. 8
D.O

Answers

Answer:i am pro

kExplanation:

The answer is b -2. Why because it’s electrically neutral compound

Using the figure shown, if I₃= 1.17 A, then (I₁ , I₂) A is:

a- (3.17 , 2.00)
b- (1.33 , 0.17)
c- (1.67 , 0.50)
d- (1.27 , 0.10)

Answers

The value of the current in each arm of the circuit is given by Kirchhoff's

Rules.

The correct option for (I₁, I₂) is; b-. [tex]\underline{(1.33, \ 0.17)}[/tex]

Reasons:

By Kirchhoff's junction rule, we have that the sum of current at a junction is given as follows;

[tex]\displaystyle \mathbf{ \sum \limits_{k = 1}^ n I_K} = 0[/tex]

Which by the direction of the currents in the given circuit diagram, we have;

I₁ - (I₃ + I₂) = 0

Therefore;

I₁ = I₃ + I₂

According to Kirchhoff's loop rule theory, we have;

[tex]\displaystyle \mathbf{\sum \limits_{k = 1}^ n V_K} = 0[/tex]

In the loop having the 2 Volts emf., we have;

-I₃·R₁ + 2 + I₂·R₂ = 0

I₃ = 1.17 A

R₁ = 2 Ω

R₂ = 2 Ω

Which gives;

-1.17 × 2 + 2 + I₂×2 = 0

I₂ × 2 = 2.34 - 2 = 0.34

I₂ = 0.34 ÷ 2 = 0.17

I₂ = 0.17 A

From the loop having the 7 Volts emf. we have;

7 - 0.17×2 - I₁ × 4 - I₁ × 1 = 0

Which gives;

7 - 0.34 - 5·I₁ = 0

5·I₁ = 7 - 0.34 = 6.66

I₁ = 6.66 ÷ 5 = 1.332

Therefore;

[tex]\underline{\mathbf{(I_1, \, I_2)} = (1.33, \, 0.17)}[/tex]

Learn more about electric circuits here:

https://brainly.com/question/2608877

A first order reaction is 25% completed in 1h minutes. Calculate the time required for its 50% completion.

Answers

It would be 2 hours I think

This is the question I need help with

Answers

Answer:

Explanation:

If we ASSUME that a CCW torque is positive

τ = 10sin135[8.0] - 16sin90[4.0] + 19sin160[3.0] = 12 N•m

as the result is positive, the net torque is CCW.

Other Questions
vertical and horizontal asymptotes what is 17/5 - 16/5 as an improper fraction What is an equation in slope-intercept form for the line that passes through the points (1, -3) and (3,1) y= 3x + 1 y=x-3 y=2x+5 y= 2x 5 The graph of y = f(x) is shown below. What are all of the real solutions of f(x) = 0? joe, a hair dresser, offers students a discount price on haircuts. this form of pricing is an example of what is the keyboard shortcut to display formulas on the worksheet STOL0will eat the hamburgLook at the pictures. What's going to happen? Make sentences with3. I will gh it4.3.2. Exercise 8Vare going to + verb.1. It's going to rain.02.3.4.5.6.7.TEACHYouTAPANESEVES16143.3. Choosing the correct formA: Why are you working so hard these days?B: Because I'll buy /I'm going to buy a car, so I'm saving as musas I can.A: What will you buy / are you going to buy for her birthday?B: A CD.the broasane obou to fall out theteacherO Determine the highest occupied energy level in thefollowing elements:a. Heb. Bec. Ald. Cae. Sn can you help me solve 4x - 15 = 17 - 4x PLEASE HELP ME I NEED HELP the presence of a lophophore in a newly discovered species would suggest that the species ________. how many supreme court justices did trump nominate help now plsssssssssssssssssssssssss What was the major difference between the powers of emperors in the east and west? Question 7 high school geometry. Carbon has a half-life of 5,730 years and you found a fossil with 4 atoms of Carbon and 12 atoms ofNitrogen, how old would it be?a. 0 years oldb. 5,730 years oldc. 11,460 years oldd. 17,190 years old Soil degradation, rising population, water scarcity, and a lack of capital put which of the following regions at the greatestrisk for famine and malnutrition?A. Central AmericaB. sub-Saharan AfricaC. Western EuropeD. North AmericaPlease select the best answer from the choices provided.AB00BD 3. What is the exact area of triangle ABC? Use special right triangles to help find the base of the triangle. Show your work. What is the type of cell show in the circle plant cell,prokaryote cell,eukaryotic cell,egg cell? How many moles of chlorine could be produced by decomposing 157g NaCl? 2NaCl --> 2Na+Cl2