how does she hold a newspaper while reading without using the lens? why?​

Answer:

13.759 % of the initial mechanical energy is lost as thermal energy.

Explanation:

By the First Law of Thermodynamics we know that increase in internal energy of the object ([tex]U[/tex]), in joules, is equal to the lost amount of the change in gravitational potential energy ([tex]U_{g}[/tex]), in joules:

[tex]\frac{x}{100} \cdot \Delta U_{g} = \Delta U[/tex] (1)

Where [tex]x[/tex] is the percentage of the energy loss, no unit.

By definition of the gravitational potential energy and internal energy, we expand this equation:

[tex]\frac{x\cdot m \cdot g \cdot h}{100} = m\cdot c\cdot \Delta T[/tex] (1b)

Where:

[tex]m[/tex] - Mass of the object, in kilograms.

[tex]g[/tex] - Gravitational acceleration, in meters per square second.

[tex]h[/tex] - Initial height of the object above the lunar ground, in meters.

[tex]c[/tex] - Specific heat of aluminium, in joules per degree Celsius-kilogram.

[tex]\Delta T[/tex] - Temperature increase due to collision, in degree Celsius.

If we know that [tex]m = 0.95\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]h = 75\,m[/tex], [tex]c = 920\,\frac{J}{kg\cdot ^{\circ}C}[/tex] and [tex]\Delta T = 0.11\,^{\circ}C[/tex], then the percentage of energy loss due to collision is:

[tex]x = \frac{100\cdot c\cdot \Delta T}{g\cdot h}[/tex]

[tex]x = \frac{100\cdot \left(920\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (0.11\,^{\circ}C)}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (75\,m)}[/tex]

[tex]x = 13.759\,\%[/tex]

13.759 % of the initial mechanical energy is lost as thermal energy.

Answer:

25 mm = 0 deg C

200 mm = 100 deg C

200 - 25 = 175 = change in thread per 100 deg C

95 - 25 = 70 mm - change in thread from 0 deg C

70 / 175 * 100 = 40 deg C    final temperature at 95 mm

Answer:

The momentum makes it worse.

Explanation:

The momentum of vehicles running at faster speeds is very high and causes a lot of damage to the vehicles.

Answer:

Velocity is the rate of change of position with respect to time, whereas acceleration is the rate of change of velocity. Both are vector quantities (and so also have a specified direction), but the units of velocity are meters per second while the units of acceleration are meters per second squared.

Answer:

B. Km/s/hr

Explanation:

Answer:

electric current=ampere(A)

force=Newton (N)

area=metres square(m^2)

power=watt(w)

density=kg/m3 

amount of substance =mole per cubic meter (mol/m3).

volume=cubic meter (m3),

Answer:

thanks for brainlist brother.........

Answer:

The force applied to make the object move

Answer:

input work = output work

E * ED = L* LD

Explanation:

The principle of lever is that input work is always equal to output work .

Answer:

(a) 11.3 T

(b) 6.09 T

Explanation:

Current, I = 14 kA = 14000 A

number of turns, N = 900

inner radius, r = 0.7 m

outer radius, R = 1.3 m

The magnetic field due to a circular coil is given by

[tex]B = \frac{\mu o}{4\pi}\times \frac{2 N\pi I}{R}[/tex]

(a) The magnetic field due to the inner radius is

[tex]B = 10^{-7}\times \frac{2\times 900\times 3.14\times 14000}{0.7}\\\\B = 11.3 T[/tex]

(b) The magnetic field due to the outer radius is

[tex]B = 10^{-7}\times \frac{2\times 900\times 3.14\times 14000}{1.3}\\\\B = 6.09 T[/tex]

The dimension of a/b where x is the distance and t is the time is T

Given the expression

x = at + bt²

where

x is the distance

t is the time

Based on the homogeneity principle, the expression on the left-hand side must be equal to that on the right. Hence;

x = at

[tex]a = \frac{x}{t}[/tex]

Since x is the distance and distance is measured in metres, the dimension equivalent will be the length 'L'

Since t is the time and time is measured in seconds, the dimension equivalent will be the seconds 'T'

[tex]a=\frac{L}{T}[/tex]

Similarly;

x  = bt²

[tex]b=\frac{x}{t^2}\\b=\frac{L}{T^2}[/tex]

Next is to get a/b;

[tex]\frac{a}{b} = \frac{L}{T} \div \frac{L}{T^2}\\\frac{a}{b} = \frac{L}{T}*\frac{T^2}{L} \\\frac{a}{b} =\frac{T^2}{T}\\\frac{a}{b} =T[/tex]

Hence the dimension of a/b is T

Answer:

120 Nm-1

Explanation:

Según la ley de Hooke;

F = Ke

F = fuerza sobre el resorte

K = constante de fuerza

e = extensión

Por eso;

K = F / e

K = 24N / 20 × 10 ^ -2m

K = 120 Nm-1

Gamma rays

used in radiotherapy

Answer:

asdiieiwihebebwiwo3o2iwjw3

Answer:

D. crystalline solid that conducts current under certain conditions

Explanation:

Semiconductors are crystalline solids that has the ability to conduct electrical currents but on certain conditions e.g heat. The conduction of semiconductors is less than that of conductors (metals) but more than insulators (nonmetals), hence, they are said to be intermediates of conductors and insulators in terms of electrical conductivity.

Examples of semiconductors are silicon, boron, carbon, germanium, arsenic etc.

Answer:

Rotational kinetic energy

Explanation:

It is caused by circular motion.

Answer:

Standard units are the units we usually use to measure the weight, length or capacity of objects.

Answer:

THE SYSTEM OF UNITS WHICH IS AGREED BY THE INTERNATIONAL CONVENTION OF SCIENTISTS HELD IN FRANCE IN 1960 IS CALLED SI SYSTEM.

Answer:

SI unit is an internationally accepted system and have the same value all over the world .

I don't know the importance sotry

Answer:

SI unit is an internationally accepted system that have same value all over the world.

Answer:

D. Meters/Seconds

Explanation:

The time period of a wave is measured in seconds.

A typical wave involves both time and distance.  Consider a sound wave, which is basically a periodic modulation of the local air pressure.  We "hear" the sound because our ears respond to the variations of pressure.

The most common metric of a sound wave is frequency.  This is the rate at which the change in pressure occurs, and is measured in cycles per second, formally known as "hertz".  The period is the inverse of frequency andl has the units of seconds per cycle, commonly stated simply as seconds.

Answer:

the specific heat capa city of the aluminium is 900 joules per kilogram per °C.

Am I right please?

Answer: The answer is B

Explanation:

There are 4 fundamental forces that hold matter together.

- Gravitational Force

- Electromagnetic Force

- Strong Nuclear Force

- Weak Nuclear Force

We have barely just scratched the info about nuclear forces but the reason why B is the answer to the question is that Strong nuclear force actually holds the protons and neutrons together in the nucleus of an atom, much like the picture in B.

Answer: B

Explanation:

That's a parallel circuit. (B)

When current from Point-A reaches the 3-way intersection just to the right of Point-B, it has to make a choice:  Either turn left, go through B, and light the lower bulb, or go straight and light the upper bulb.

A circuit that has any "decision" points in it is a parallel circuit.  What happens in the real world is:  The current splits up.  Some of the current that reaches the intersection turns left toward Point-B, and the rest of it goes straight up.

A series circuit is one in which there's only one possible path all the way around.  There are no intersections of more than 2 roads, and no electron ever has to decide which way to flow.

An open circuit is one in which there's a break somewhere along the line and electrons can't jump across it.  It's like a railroad where a big piece is cut out of the track somewhere.  So no trains can travel on that route, and there's no current flowing anywhere in the circuit.

I'm not so sure about a "combination" circuit.  I guess you could give that name to a complicated circuit that has some series parts and some parallel-parts.  Personally, I'd call that a "series-parallel" circuit.  But it really doesn't matter right now.  Whatever the word means, the circuit in the picture is definitely not a "combination" circuit.

Answer:

B. Parallel Circuits

Explanation:

A parallel circuit is constructed by connecting the terminals of all the individual load devices so that the same value of voltage appears across each component. In a parallel circuit, charge divides up into separate branches such that there can be more current in one branch than there is in another.

hope i helped

Tenemos un problema de termodinamica sobre gases ideales, los cuales pueden ser descritos por la ecuación de estado del gas ideal

[tex]P*V = n*R*T[/tex]

donde:

P = presión

V = volumen

n = número de moles

R = constante de los gases

T = temperatura.

1) Para el primer problema podemos pensar que el gas dentro del globo es un gas ideal:

Originalmente sabemos que n = 4 y V = 5.0 L

Entonces tendremos:

[tex]P*(5.0 L) = (4 moles)*R*T[/tex]

Ahora decidimos agregar 8 moles más, dejando constante la presión y la temperatura, entonces podemos reescribir la ecuación de arriba como:

(5.0L)/(4 moles) = R*T/P

Y como R, T y P son constantes, entonces:

R*T/P es una constante.

Esto quiere decir que cuando agreguemos 8 moles, para tener un total de 12 moles, tendremos que:

V'/(12 moles) = R*T/P = (5.0L)/(4 moles)

Donde V' es el nuevo volumen final del globo, y es lo que queremos obtener.

V'/(12 moles) =  (5.0L)/(4 moles)

V' =   (5.0L)*(12 moles)/(4 moles) = (5.0 L)*3 = 15.0 L

2) Queremos obtener la densidad en gramos sobre litro de un gas con una masa molar de 60g/mol, a P = 0.75 atm y T = 25°C.

Primero pasemos la temperatura a grados kelvin:

T = 25°C = (25 + 273.15)°K = 298.15°K

Planteamos la ecuación del gas ideal:

[tex]P*V = n*R*T[/tex]

reemplazando R = 0.082 (atm*L/mol*k), además de la presión y la temperatura para un solo mol de gas:

[tex](0.75 atm)*V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)[/tex]

Resolviendo para V obtenemos que:

[tex]V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)/(0.75 atm) = 32.597 L[/tex]

Así, vemos que un mol de este gas ocupa un volumen de  32.597 L

Y también sabemos que un mol de este gas pesa 60 gramos.

Recordando que la densidad es el cociente entre la masa y el volumen, podemos ver que la densidad del gas será:

[tex]d = 60g/(32.597 L) = 1.84 g/L[/tex]

Si deseas leer mas sobre el tema, podes ver:

https://brainly.com/question/18528542

Answer:

A. Contains DNA

C. Contains ribosomes

F. Lacks a nucleus

Explanation:

Explanation:

The derivative of a constant term is always 0. So the acceleration of the body would be zero. Hence, the acceleration of a body moving with uniform velocity will always be zero.

hope it helps you

Answer:

electric current is derived unit.

Explanation:

According to the definition of electric current, it appears to be a derived quantity. Charge on the other hand seems more fundamental than electric current.

Answer:

D)0.0889kg

Explanation:

If a large atomic bomb produces around 8.00x10¹⁵J of energy, then from Einstein's energy law i.e E=mc² we can calculate that the amount of matter is  0.0889kg. The correct option is D.

The Einstein Energy Law, often referred to as Einstein's famous equation relates the energy of a particle (E) to its mass (m) and the speed of light (c). The equation is as follows:

E = mc²

This equation shows that energy (E) and mass (m) are equivalent and interchangeable and that a small amount of mass can be converted into a large amount of energy. This is the basis for understanding nuclear reactions and the energy released in processes like nuclear fusion and fission.

Here in the question,

To calculate the mass that is converted into energy in an 8.00x10¹⁵J nuclear reaction, we can rearrange the equation to solve for m:

m = E / c²

where c = 3 x 10⁸ m/s is the speed of light in a vacuum.

Substituting the values, we get:

m = 8.00x10¹⁵ J / (3 x 10⁸ m/s)²

m = 0.0889kg

Therefore, a large atomic bomb that produces around 8.00x10¹⁵ J of energy converts approximately 0.0889kg of matter into energy. This is a very small amount of matter, but because c² is such a large number, a huge amount of energy can be released from a small amount of matter in a nuclear reaction.

To learn more about Einstein's energy law click:

https://brainly.com/question/2292817

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Answer:

The separation between the two stones is 36 m, when the second stone is approximately 10.9 m below the top of the cliff

Explanation:

The given parameters are;

The height of the cliff from which the stones are dropped, h = 60 m

The time at which the second stone is dropped = 1.6 seconds after the first

The distance below the top of the cliff when the distance between the two stones is 36 m = Required

We have;

The kinematic equation of motion that can be used is s = u·t - (1/2)·g·t²

For the first stone, we have, s₁ = u·t₁ - (1/2)·g·t₁²

For the second stone, we get; s₂ = u·t₂ - (1/2)·g·t₂²

t₁ = t₂ + 1.6

g = The acceleration due to gravity ≈ 9.81 m/s²

s = The distance below the cliff top

The initial velocity of the stones, u = 0

Let t represent the time from which the second stone is dropped at which the distance between the two stones is 36 m, we have;

s₁ = u·(t + 1.6) + (1/2)·g·(t + 1.6)²

s₂ = u·t + (1/2)·g·t²

u = 0

∴ s₁ - s₂ = 36 =  (1/2)·g·(t + 1.6)² - (1/2)·g·t²

2 × 36/(g) = (t + 1.6)² - t²  = t² + 3.2·t + 2.56 - t² = 3.2·t + 2.56

2 × 36/(9.81) = 3.2·t + 2.56

t = (2 × 36/(9.81) - 2.56)/3.2 =  ≈ 1.49 s

t ≈ 1.49 s

s₂ = (1/2)·g·t²

∴ s₂ = (1/2) × 9.81 × 1.49² ≈ 10.9

The distance below the top of the cliff of the second stone when the the separation between the two stones is 36 m, s₂ ≈ 10.9 m.

Answer:

Option A.

Explanation:

We define the half time T as the time such that an initial quantity A reduces to its half.

So we can model the quantity as a function of time like:

P(t) = A*e^(-k*t)

Then for the half time, T, we will have:

P(T) = A/2 = A*e^(-k*T)

solving for k, we get:

A/2 = A*e^(-k*T)

1/2 = e^(-k*T)

ln(1/2) = ln( e^(-k*T)) = -k*T

-ln(1/2)/T = k

Here we know that the half time is T = 26.5s

if we input that in the above equation, we get:

-ln(1/2)/26.5s = k = 0.0262 s^-1

Then the correct option is A

Answer:

Obeying to weights & measurement regulations in both national and international metrology legislation, standards and test procedures is a requirement to participate in any market because it's aimed to safeguard the consumers and promote fair competition, which provides efficiency and saves unnecessary costs to U.S. businesses and stakeholders.

Explanation:

In the U.S., the National Institute of Standards and Technology (NIST) has an Office of Weights and Measures (OWM) that represents the country in the International Organization of Legal Metrology (OIML)

Answer:

the magnetic compass is used to determine direction because it is one of the most accurate form of magnet as we already know that a freely suspended magnet always faces towards north direction and south direction