John walked from his home to work, it took him 12 min and the distance covered was 3 km. calculate the average speed in m/s

Answer:

To check whether a chemical equation is balanced or not we usually look if elements on the product side are numerically equal to the reactant side or not.

A. Na + MgCl₂ → NaCl + Mg

Reactant Product

Na = 1 1

Mg = 1 1

Cl = 2 1

Unbalanced

B. 2LiOH + H₂S → Li₂S + 2H₂O

Reactant Product

Li = 2 2

S = 1 1

O = 2 2

H = 4 4

Balanced

C. AgNO₃ + NaCl → NaNO₃ + AgCl

Reactant Product

Ag = 1 1

N = 1 1

Na = 1 1

Cl = 1 1

O = 3 3

Balanced

D. 3PBr₃ + 2Cl₂ → 3PCl₃ + 2Br₂

Reactant Product

P = 3 3

Br = 9 4

Cl = 4 9

Unbalanced

Therefore, equations B and C are balanced chemical equations.

The elapsed time when the particle returns to the origin is determined from the ratio of initial velocity and acceleration of the particle.

The time of motion of the particle is calculated by applying Newton's second law of motion.

F = ma

F = m(v)/t

where;

a = v - u/t

v = u + at

when the particle returns to the origin, direction of u, = negative.

final velocity = 0

0 = -u + at

at = u

t = u/a

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The component form of the vector - u + w is determined as  -2i + 3j.

The component vector V is calculated from the summation of vector U and vector W.

v = -u + w

Given;

v = -(2i - j) + i + 2j

v = -2i + j + 2j

v = -2i + 3j

                                     y - axis        

                                        ↑  

                                        ↑  

                                        ↑ 3j

                                        ↑

x - axis  ←    ←    ←    ←    ←

                      2i

The complete question is below:

if u = 2i - j  and w = i + 2j, find the component form of ~v = -u + w~ and sketch the specified vector operations geometrically.

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The magnetic field due to a  very long wire with current A is 6.67 x 10⁻⁷ A (Tesla).

This is the region of space where the effect of magnetic force is felt.

The magnetic field due to a current carrying conductor is calculated as;

B = μI/2πd

where;

at a distance of 0.3 m

B = μI/2π(0.3)

B = 0.53μI

B = 0.53 x (4π x 10⁻⁷)I

B = 6.67 x 10⁻⁷ A (Tesla)

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Answer:

8.35 ×[tex]10^{-3}[/tex] kg

Explanation:

Remember the formula for heat:

[tex]Q=mc\Delta T[/tex]

You just need to solve for m, doing so you're left with:

[tex]m=\dfrac{Q}{c\Delta T}[/tex]

Replace the variables with numbers and that's it.

The mass of a sample of water is 0.841 kg.

Specific heat is the amount of heat energy required to raise the temperature of one unit of mass of a substance by one degree Celsius (or Kelvin). It is a characteristic property of a substance that reflects its ability to store and release thermal energy.

Different substances have different specific heat capacities, depending on their chemical composition and physical properties. For example, water has a high specific heat capacity of 4,200 joules per kilogram per degree Celsius (J/kg°C), which means that it takes a large amount of heat energy to raise the temperature of water by one degree Celsius. In contrast, metals such as copper and aluminum have much lower specific heat capacities, which means that they heat up and cool down more quickly than water when subjected to the same amount of heat energy.

The specific heat of a substance can be measured experimentally using calorimetry, which involves measuring the amount of heat energy absorbed or released by a substance as it undergoes a change in temperature. The specific heat of a substance is an important parameter in many fields of science and engineering, including thermodynamics, materials science, and environmental science.

Here in the Question,

We know the  formula:

Q = mcΔT

where:

Q = amount of heat lost by the sample of water, which is -870 J (negative because heat is lost)

m = mass of the sample of water, which is what we need to find

c = specific heat capacity of water, which is 4200 J/kg °C

ΔT = change in temperature, which is -24.8 °C (negative because temperature dropped)

Substituting the values, we get:

-870 J = m(4200 J/kg °C)(-24.8 °C)

Simplifying, we get:

m = -870 J / (4200 J/kg °C × -24.8 °C)

m = 0.841 kg

Therefore, the mass of the sample of water is 0.841 kg.

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Hope this helps.

Good luck ✅.

The final temperature of the given mass of water at the initial temperature is 45.8 ⁰C.

The change in temperature of the water is calculated as follows;

Q  = mcΔθ

Δθ = Q/mc

where;

Δθ = (10,000)/(0.1 x 4200)

Δθ = 23.8

T2 - T1 = 23.8

T2 = 23.8 + 22

T2 = 45.8 ⁰C

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The electric potential energy in a capacitor will be 5 × 10 ⁻⁹ J.

A capacitor is a device that can store electrical energy. It is a two-conductor configuration separated by an insulating medium that carries charges of equal size and opposite sign.

An electric insulator or vacuum, such as glass, paper, air, or a semiconductor termed a dielectric, can be used as the non-conductive zone.

The  electric potential energy in a capacitor is found as;

[tex]\rm E = \frac{1}{2} QV[/tex]

[tex]\rm E = \frac{1}{2}\times 1.0 \times 10^{-10} \ C \times 100 \ V \\\\ E= 5 \times 10^{-9} \ J[/tex]

Hence the electric potential energy in a capacitor will be 5 × 10 ⁻⁹ J.

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Answer:

B

Explanation:

Remember:

F = m * a

 =  10 * 2  = 20 N

Answer:

200 j is kinetic energy of mass

density = mass / volume

mass = 81.34 - 62

= 19.34 g

volume = 24.6 ml

density = 0.786 g/ml

Answer:

2.8125 meters

Explanation:

I will assume 7.5 m/s

When the Kinetic Energy is entirely converted to Potential energy the max height will have been reached

KE = PE

1/2 m v^2 = mgh     divide by m

1/2 v^2 = gh         looking for  h     so divide both sides by

1/2 v^2 / g   = h      sub in the values   using g = 10 m/s^2

1/2 ( 7.5 )^2 / 10  = 2.8125 m

Answer:

Average acceleration = 12m/s^2

Explanation:

Acceleration is equal to the change in velocity over the change in time:

[tex]a=\frac{\Delta v}{\Delta t}[/tex]

Change in velocity is the final velocity minus the initial.

We are told the car goes from 0 to 26.8 m/s making 26.8 our final and 1 our initial. Therefore the change in velocity is 26.8-0 = 26.8m/s. ([tex]\Delta v[/tex])

And that this happens over 2.2s so this is our change in time: [tex]\Delta t[/tex]

Therefore our acceleration is: [tex]a = \frac{26.8}{2.2}[/tex]

Acceleration = 12.18 m/s^2

Rounded to 2 significant figures (2s.g. in 2.2s), the answer is 12m/s^2.

Hope this helped!

Answer: I believe his brother, Mike, who is 6'2, will have the longer shadow.

Answer:

decrease,inverse

Explanation:

........................

Answer:

35

Explanation:

total magnification = eyepiece lens x objective lens

TM = 10X x 25X

TM = 250X

To identify a satirical tone, look for words an author uses to exaggerate a particular character behavior to make that person appear ridiculous to the reader. The statement is True.

What a person thinks upon a situation and get through it makes the character of a person and defines his behavior.

Given is a statement "To identify a satirical tone, look for words an author uses to exaggerate a particular character behavior to make that person appear ridiculous to the reader".

The words used by the person forms the character. So, the author searches for the word which says about his character but the reader finds it ridiculous.

Thus, the statement is true.

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Answer:

People with presbyopia require a convex lens for reading glasses; specialized preparations of convex lenses usually require the services of an optometrist

Explanation:

hope it will help you understand, if you have any questions just let me know.

a)  p₀ = 1.2 kg m / s

b) p_f = 1.2 kg m / s  

c)    [tex]v_{2f}[/tex] = 1.278 m/s

d)1.2482 =[tex]v_{2f}[/tex] cos θ

e)  0.2736 =[tex]v_{2f}[/tex]sin θ

g) θ = 12.36

Momentum is the product of the mass of a particle and its velocity. Momentum is a vector quantity; i.e., it has both magnitude and direction.

According to the question,

We define a system formed by the two balls, which are isolated and the forces during the collision are internal.

Hence , the momentum is conserved

a) The momentum of the system before the collision:

[tex]p_o = m v_1_0 + 0 p_o= 0.6 2 p_o = 1.2 kg m / s[/tex]

b) The momentum of the system after the collision, as the system is isolated, the momentum is conserved so

[tex]p_f = 1.2 kg m / s[/tex]

d. On X axis

[tex]p_ox[/tex] = 1.2 kg m / s

[tex]p_{fx}[/tex]= m v1f cos 20 + m v2f cos θ

[tex]p_o = p_f[/tex]

1.2 = 0.6 (-0.8) cos 20+ 0.6[tex]v_{2f}[/tex] cos θ

1.2482 =[tex]v_{2f}[/tex] cos θ

e. On Y axis  

[tex]p_{oy} = 0[/tex]

[tex]p_{fy}[/tex]= m[tex]v_{1f}[/tex]sin 20 + m[tex]v_{2f}[/tex]cos θ

0 = 0.6 (-0.8) sin 20 + 0.6 [tex]v_{2f}[/tex] sin θ

0.2736 =[tex]v_{2f}[/tex]sin θ

Here,

g. we write our system of equations

0.2736 =[tex]v_{2f}[/tex] sin θ

1.2482 = [tex]v_{2f}[/tex] cos θ

0.219 = tan θ (divide)

θ = tan⁻¹ 0.21919

θ = 12.36

c. Now To find the velocity

0.2736 = [tex]v_{2f}[/tex] sin θ

[tex]v_{2f}[/tex]= 0.2736 / sin 12.36

[tex]v_{2f}[/tex] = 1.278 m / s

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Answer:

The efficiency of a simple machine is defined as the ratio of useful work done by a machine (output work) to the total work put into the machine (input work). For ideal or perfect machine, work output is equal to the work input.

Explanation:

Hope it Helps!!!

The halo of galaxy expand from the bulge out to the edge of the disk. The correct option is b.

Universe is the whole cosmic system of matter and energy. The Earth, the Sun, the Moon, the planets, the stars along with the ,dust , gases, rocks forms the universe.

It went on expanding and stretched to grow as large as possible. It is still now expanding.

The universe consist of fully dark matter, interstellar gases or dust. The  This universe began with a big bang , also known as the massive explosion. This universe is still on it way of expanding more.

The formation of stellar halos occurs naturally in a cold dark matter. Universe has halos which occurs from the bottom-up or the large structure of galaxies is formed starting with small objects.

Thus, the correct option is b.

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Answer:

34g

(second option listed)

Explanation:

half life is the number of days it takes to decrease by half,

after 8 days you are left with half of the original portion

in a period of 32 days, we experience 4 repeats of 8 days

(it gets cut in half four times):

544 / 2 = 272  {day 8}

272 / 2 = 136  {day 16}

136 / 2 = 68 {day 24}

68 / 2 = 34 {day 32}

so, after 32 days, 34g of ooblek are left un-decayed

hope this helps!! have a lovely day :)

The mass of the metre stick given the data from the question is 150 g

Clock wise moment = Anticlockwise moment

M × 25 = 150 × 25

M × 25 = 3750

Divide both sides by 25

M = 3750 / 25

M = 150 g

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The first law of thermodynamics is similar to the conservation of energy because both state that this element (i.e., energy) is not created/destroyed in the universe.

The first law of thermodynamics is a popular law in physics that states change in internal energy is equal to the energy added and the work made by a closed system.

Moreover, the law of conservation of energy states that it cannot be created/destroyed in the Universe, which is deeply associated with principles of thermodynamics.

In conclusion, the first law of thermodynamics is similar to the conservation of energy because both state that this element (i.e., energy) is not created/destroyed in the universe.

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The law of the conservation of energy relates to the first law of thermodynamics by the fact that the former forms the basis for the latter.

It follows from the study of physics that the basis for the postulation of the First law of thermodynamics is on the basis of the law of conservation of energy, which states that energy can neither be created nor destroyed, but can be transferred between forms.

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The variable that is altered by the independent variable is called the dependent variable. the spectrum given out by the hypothetical unknown celestial object.

Name : Christopher Andre

Instructor name : Albert brown

Name of the lab : ELS Laboratory

The term electromagnetic spectrum refers to the range of electromagnetic radiation's frequencies, as well as the wavelengths and photon energies connected to each frequency.

By analyzing the absorption spectra of the planets and moons, the electromagnetic spectrum experiment seeks to identify the components that make up their atmospheres.

From below one hertz to over 1025 hertz, electromagnetic waves are included in the electromagnetic spectrum.

The wavelengths that correlate to the frequency range from tens of thousands of kilometers to a small portion of the size of an atomic nucleus.

Starting at the low frequency (long wavelength) end of the spectrum, each frequency band's electromagnetic waves are referred to by a variety of names.

Hence the dependent variable is the one that changes as a result of the independent variable.

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a. The free-body diagram for the glass when it is at the top of the circle is attached below.

b. The equation for the net force on the glass at the top of the circle in terms of w, Fn, m, v, and r is mg x g + N - mg x Vtop² /R =0

c. The glass will fall out of the bucket if the normal force between the glass and bucket equals zero. The speed with which she spin the bucket to prevent this from happening is 3.83 m/s.

d. The string will break if the tension on it is more than 100 N. The range of speeds can prevent the string from breaking is 3.83< Vtop<4.99 m/s

When two or more forces are acting on the system of objects, then the to attain equilibrium, net force must be zero.

Given, Angela has a bucket of mass 2 kg tied to a string. She places a drinking glass of mass 0.5 kg in the bucket. She spins the bucket in a vertical circle of radius 1.5 m. She must swing the bucket to keep the glass from falling out.

a. The free body diagram of the bucket and glass is attached below.

b. Bucket will undergo centrifugal force

Fb = mVtop² /R

From the equilibrium of forces, we have

For bucket,

T +mb xg - N = mb x Vtop² /R..............(1)

For glass,

mg x g + N = mg x Vtop² /R..............(2)

Thus, this is the net force equation on the glass.

c. On adding both the equations. we have

T + (mb + mg) xg = (mb + mg) Vtop² /R

Substituting the values, T = 0 and from the question, we get

0 + (2+0.5) 9.81 = (2+0.5)(Vtop²/0.5)

Vtop = 3.83 m/s

Thus, the speed of spin to prevent glass from falling out is 3.83 m/s

d. The string will break if the tension on it is more than 100 N

100 + (2+0.5) 9.81 = (2+0.5)(Vtop²/0.5)

Vtop = 4.99 m/s

Thus, the range of velocity is 3.83< Vtop<4.99 m/s

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When a substance changes from a liquid to a solid, they move more slowly and become fixed in position. Option A is correct.

When a substance changes from a liquid to a solid, its particles lose energy and move more slowly. As the temperature decreases, the particles lose kinetic energy and start to arrange themselves into a fixed, ordered pattern. This causes the substance to solidify and the particles become fixed in position.

The transition from a liquid to a solid state is called freezing or solidification. During this process, the particles lose energy and their motion becomes more restricted, causing them to move more slowly and eventually become fixed in position. Option A is correct.

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The main advantage of hydroelectric energy is the fact that it is a renewable energy source (Option C).

Hydroelectric energy refers to the energy from water bodies that can be used to generate electricity.

Hydroelectric energy is stored as potential energy and then converted to kinetic motion energy to be converted into electricity.

Hydroelectric energy is renewable because it is indefinitely generated by water bodies in nature.

In conclusion, the main advantage of hydroelectric energy is the fact that it is a renewable energy source (Option C).

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