an elastic cord 61 cm long when a weight of 75N hangs from it, but 85cm when a weight of 210N hangs from it. what is the spring constant of the cord

Answer:

The actual height of the tree is 28 m

Explanation:

The given information are;

The length of the shadow of an upright meter rule = 25 cm

The actual height of the meter rule = 100 cm

The length of the shadow of the tree = 7 m

The actual  height of the tree  = h

We have

[tex]\dfrac{The \ length \ of \ the \ shadow \ of \ an \ upright \ metre \ rule}{The \ actual \ height \ of \ the \ metre \ rule} = \dfrac{The \ length \ of \ the \ shadow \ of \ the \ tree}{The \ actual \ height \ of \ the \ tree}[/tex]Which gives;

[tex]\dfrac{25 \ cm}{100 \ cm} = \dfrac{7 \ m}{The \ actual \ height \ of \ the \ tree}[/tex]

Therefore;

[tex]The \ actual \ height \ of \ the \ tree = 7 \ m \times \dfrac{100 \ cm}{25\ cm} = 7 \ m \times 4 = 28 \ m[/tex]

That is the actual height of the tree = 28 m.

Answer: It is given that A body weighs 20gf in air and 18. 0gf in water. Hence, the answer X-3 = 7.

Answer:

A car driving in a straight line 20 m/s

Explanation:

ayepecks silly

Answer:

a commutator

Explanation:

Answer:

1525 meters above ground

Explanation:

So to do this you will need to write this in slope intercept form or [tex]y=mx+b[/tex]. So 650 would be the b, 175 would be the m, and the x would be 5 so the equation would be [tex]y=175(5)+650[/tex] so if you solve or simplify the equation you will get 1525 meters above the ground and that would be our final answer.

Answer:

b. Red light is transmitted through and reflected by the glass

Explanation:

Give me brainliest plz!

All of the wavelengths of the red light are absorbed when it passes through a translucent red glass window, but the red light is transmitted and reflected.

Therefore, the correct answer is option b) Red light is transmitted through and reflected by the glass.

To learn more about light refer to:

https://brainly.com/question/12002703

#SPJ2

Answer:

the skateboard pushes up

Explanation:

newton's 3rd law says for every action, there's an equal and opposite reaction, so when his feet push on the skateboard, the skateboard pushes back up.

Answer:

the skateboard pushes up

Explanation:

Question

The large-scale distribution of galaxies in the universe reveals

A) a smooth, continuous, and homogenous arrangement of clusters

B) large voids, with most of the galaxies lying in filaments and sheets a large supercluster at the center of the universe

C) a central void with walls of galaxies at the edge of the universe

Group of answer choices

Answer:

The correct answer is B)

Explanation:

The universe is arranged in a filamentary structure. Filamentary structures are very large. They are the largest kind of structures in the universe and comprise mostly of galaxies that are held together by gravity.

The structures found within Galaxy filaments have thread-like qualities spanning 52 to 78.7 megaparsecs h⁻¹ in lenght.

Other phenomena associated with the nature fo the universe is the existence of void spaces.

Cheers!

Answer:

Explanation:

In this problem we are required to find the potential energy possessed by the television

Given data

mass of television m = 15 kg

height  added above the ground, h= 1-0.3 = 0.7 m

acceleration due to gravity g = 9.81 m/s^2

apply the formula for potential energy we have

P.E= m*g*h

P.E = 15*9.81*0.7 = 103 Joules

Answer:

(a) 17.0eV

(b) 10.55W

Explanation:

(a) The amount of work done (W) on an electron by an ideal battery of emf value of V as it moves from the positive to the negative terminal is given by;

W = q x V                 --------(i)

Where;

q = charge on the electron = 1e

From the question;

V = 17.0 V

Substitute the values of q and V into equation (i) as follows;

W = 1e x 17.0

W = 17.0eV

Therefore, the work done in electron volts is 17.0

(b) The power (P) of the battery as some electrons (n) pass through it at time t, is given as;

P = (n q V) / t            --------------(ii)

Where;

n = number of electrons = 3.88 x 10¹⁸

t = 1s

q = 1.6 x 10⁻¹⁹C

V = 17.0V

Substitute these values into equation (ii) as follows;

P = (3.88 x 10¹⁸ x 1.6 x 10⁻¹⁹ x 17.0) / 1

P = 10.55W

Therefore the power of the battery is 10.55W

Answer:

A

Explanation:

Answer:

Explanation:

Reddening of sun's rays at sunset and sunrise is due to scattering of light . The white light consisting of seven colours coming from the sun are scattered in different directions when they fall on the air particles present in atmosphere . Red coloured light scatters least and it travels straight forward to the viewer on the earth . On the other hand other colours scatter most and therefore they go out of area of vision for the viewer on the earth . Since only red colour reaches the eye of the viewer , sun's ray appear red . This happens during sunrise and sunset . It is so because during this period , sun rays travel far greater distance through  atmosphere , so scattering is most pronounced .

Answer:

-4m/s

Explanation:

use the formula

[tex]f = ma[/tex]

where f-force

m-mass

a-accleration

so

1kN=1000N

so apply

4000=1000×a

a=4m/s

(the negative is because the car was braking)

Answer:

Your answer is -4 m/s^2

Explanation:

Set Up: Let +x be the direction the car is traveling.  

List the known & unknown quantities:  

   m = mass of the car = 1000 kg

  υ = 30 m/s

  Fx = –4 kN = –4000 N (negative since it is a braking force)

  ax = acceleration =?  

Solve: Use Newton’s second law of motion.  

Fx=max    

ax=Fx/m = −4000 N /1000 kg = −4000 kg·m/s^2 / 1000 kg =−4m/s^2

Answer:

1.01×10^20 molecules of ozone.

Explanation:

Data obtained from the question include:

Volume (V) = 2 L

Temperature (T) = 275 K

Pressure (P) = 1.89×10¯³ atm

Gas constant (R) = 0.0821 atm.L/Kmol

Number of mole (n) of ozone =.?

Using the ideal gas equation, we can obtain the number of mole of ozone as follow:

PV = nRT

1.89×10¯³ x 2 = n x 0.0821 x 275

Divide both side by 0.0821 x 275

n = (1.89×10¯³ x 2) /(0.0821 x 275)

n = 1.67×10¯⁴ mole.

Therefore the number of mole of ozone in 2 L of air is 1.67×10¯⁴ mole.

Finally, we shall determine the number of molecules present in 1.67×10¯⁴ mole of ozone.

This can be obtained as follow:

From Avogadro's hypothesis, 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of ozone contains 6.02×10²³ molecules.

If 1 mole of ozone contains 6.02×10²³ molecules,

therefore, 1.67×10¯⁴ mole of ozone will contain = 1.67×10¯⁴ x 6.02×10²³ = 1.01×10^20 molecules.

Therefore, 1.01×10^20 molecules of ozone are present in 2 L of air.

Even though the charge on the first object is greater, the forces that the two objects exert on each other are equal

Answer:

[tex]\omega_2=0.891\ rev/s[/tex]

Explanation:

Given that

Radius , r= 3.03 m

Mass of disk , M= 145 kg

Initial angular velocity

ω=0.681 rev/s

Mass of person , m= 65.4 kg

Velocity of person , V= 3.41 m/s

Initial mass moment of inertia

[tex]I_1= \dfrac{M\times R^2}{2}[/tex]

[tex]I_1= \dfrac{145\times 3.03^2}{2}=665.61\ kg.m^2[/tex]

Final mass moment of inertia

[tex]I_2= \dfrac{M\times R^2}{2}+m\times R^2[/tex]

[tex]I_2= \dfrac{145\times 3.03^2}{2}+65.4\times 3.03^2=1266.04\ kg.m^2[/tex]

[tex]Final\ angular\ velocity =\omega_2[/tex]

By using angular momentum equation

[tex]I_1\times \omega+m\times V\times R=I_2\times \omega_2[/tex]

[tex]665.61\times 0.681+65.4\times 3.41\times 3.03=1266.04\times \omega_2[/tex]

[tex]1129.01= 1266.04\times \omega_2[/tex]

[tex]\omega_2=\dfrac{1129.01}{1266.04}[/tex]

[tex]\omega_2=0.891\ rev/s[/tex]

Thus the angular velocity will be 0.891 rev/s

Answer:

we need it to work and without it we dont have strength to do anything

Answer:

energy is important to all living organisms. energy for producers comes from the sun, and energy for consumers comes from other living organisms. the abundance of energy available for organisms impacts the population.

Answer:

Electromagnetic introduction is the production of an electromotive force (voltage) across an electrical conductor in a changing magnetic field.

The difference between them:

A transformer is a static device which transfers a.c electrical power from one circuit to the other at the same frequency, but the voltage level is usually changed. For economical reasons, electric power is required to be transmitted at high voltage whereas it has to be utilized at low voltage from a safety point of view. This increase in voltage for transmission and decrease in voltage for utilization can only be achieved by using a step-up and step-down transformer.

Hopefully this helped.

Answer: 0.0180701 s

Explanation:

Given the following :

Length of string (L) = 10 m

Weight of string (W) = 0.32 N

Weight attached to lower end = 1kN = 1×10^3

Using the relation:

Time (t) = √ (weight of string * Length) / weight attached to lower end * acceleration due to gravity

g = acceleration due to gravity = 9.8m/s^2

Weight of string = 0.32N

Time(t) = √ (0.32 * 10) / [(1*10^3) * (9.8)]

Time = √3.2 / 9800

= √0.0003265

= 0.0180701s

Answer:

Kinetic energy.

Explanation:

Answer:

Explanation:

Given,

Mass ( m ) = 70 kg

Distance ( d ) = 4.5 m

Time taken ( t ) = 4 seconds

Power = ?

Now, applying the formula to find power:

[tex]power = \frac{work \: done}{time \: taken} [/tex]

[tex] = \: \frac{f \: \times \: d}{t} [/tex]

[tex] = \frac{m \: \times \: g \: \times \: d}{t} [/tex]

Plugging the values:

[tex] = \frac{70 \times 9.8 \times 4.5}{4} [/tex]

Calculate the products

[tex] = \frac{3087}{4} [/tex]

Divide:

[tex] = 771.75 \: watt[/tex]

Hope this helps...

Best regards!!

Answer:

34.34 °C

Explanation:

From the question,

Heat lost by the silver block = heat gained by the iron block.

cm(x-y) = c'm'(y-z)................... Equation 1

Where c = specific heat capacity of the silver block, m = mass of the silver block, c' = specific heat capacity of the iron, m' = mass of the iron. x = initial temperature of the silver block, z = initial temperature of the iron,  y = final temperature of the mixture.

make y the subject of the equation

y = (cmx+c'm'z)/(cm+c'm')............... Equation 2

Given: c = 50 g, c = 0.2350 J/g·°C, x = 100°C, m' = 50 g, c' = 0.4494 J/g.°C, z = 0°C

Substitute these values into equation 2

y = [(50×0.2350×100)+(50×0.4494×0)]/[(50×0.2350)+(50+0.4494)]

y = 1175/(11.75+22.47)

y = 1175/34.22

y = 34.34 °C

Answer:

(a) By small angle approximation, we have;

F = -2×T×Δy/l

(b) [tex]The \ frequency \ of \ oscillation, \ f = \dfrac{1}{2\cdot \pi }\cdot\sqrt{\dfrac{2 \cdot T}{l \cdot M} }[/tex]

Explanation:

(a) The diagram shows the mass, M, being restored by two equal tension, T acting on the elastic strings l, such the restoring force, F acts along the path of motion of the mass, with distance Δy

Therefore, the component of the tension T that form part of the restoring force is given as follows;

Let the angle between the line representing the extension of the elastic strings T and the initial position of the string = ∅

Then we have;

String force, [tex]F_{string}[/tex] = T×sin∅ + T×cos∅ + T×sin∅ - T×cos∅  = 2×T×sin∅

Whereby the angle is small, we have;

sin∅ ≈ tan∅ = Δy/l

Which gives;

[tex]F_{string}[/tex] = 2×T×sin∅ = 2×T×Δy/l (for small angles)

Restoring force F = [tex]-F_{string}[/tex] = -2×T×Δy/l

F = -2×T×Δy/l

(b) Given that the the tensions do not change appreciably as the mass, M, oscillates from Δy we have;

By Hooke's law, F = -k×x

Whereby Δy corresponds to the maximum displacement of the mass, M from the rest position, which gives;

Which gives;

F = M×a = -k×Δy

a =  -k×Δy/M

d²(Δy)/dt² =  -k×Δy/M

When we put angular frequency as follows;

ω² = k/M

We get;

d²(Δy)/dt² =  -ω²×Δy

Which gives;

Δy(t) = A×cos(ωt + Ф)

The angular frequency is thus, ω = √(k/M)

Period of oscillation = 2·π/ω = 2·π/√(k/M)

The frequency of oscillation, f = 1/T = √(k/M)/(2·π)

Where:

k = 2·T/l, we have;

f = √(k/M)/(2·π) = √(2·T/l)/m)/(2·π)

The frequency of oscillation is given as follows;

[tex]f = \dfrac{1}{2\cdot \pi }\cdot\sqrt{\dfrac{2 \cdot T}{l \cdot M} }[/tex]

Answer:

The flux through the sphere will remain the same, and the magnitude of the electric field will increase by four times.

Explanation:

The electric flux is the number of electric field, passing through a given area. It is proportional to the electric field strength and the area through which this field passes.

If the radius of the sphere is halved, the area of the sphere will reduce by square of the reduction, which will be four times. The electric field lines will become closer together, or technically increase by a fourth of its initial value. The resultant effect is that the electric flux will remain the same.

If originally,

Φ = EA cos∅

where Φ is the electric flux through the sphere

E is the electric field on the sphere

A is the area of the sphere.

If the area of the sphere is reduced to half, then,

the area reduces to A/4,

and the electric field increases to be 4E on the sphere.

The flux now becomes

Φ = 4E x A/4 cos∅

which reduces to

Φ = EA cos∅

which is the initial electric flux on the sphere.

Answer:

 I₃ = I₀ 0.395

Explanation:

Polarized light passing through a polarizer must comply with Malus's law

         I = I₀ cos² θ

Before starting, let's analyze the angle between the polarizers, the second has the same angle with the first and the third, so it is at the midpoint

         θ₂ = 39/2 = 19.5

now let's analyze the light that passes through each polarizer, as the incident is unpolarized through the first polarizer half the intensity comes out

          I₁ = I₀ / 2

the second polarizer comes out

          I₂ = I₁ cos² 19.5

          I₂ = I₀ / 2 cos² 19.5

through the third polarized the intensity passes

          I₃ = I₂ cos² 19.5

          I₃ = (I₀ /2 cos² 19.5) cos² 19.5

          I₃ = I₀ 0.395

Answer:

*  most of the emission would be in the infrared part, the visible radiation would be very small.

*total intensity of the semition decreases that the intensity depends on the fourth power of the temperature

Explanation:

The radiation emitted by the Sun is approximately the radiation of a black body, if the Sun were to cool, the maximum emission wavelength changes

          λ T = 2,898 10⁻³

          λ = 2,898 10⁻³ / T

if the temperature decreases the maximum wavelength the greater values ​​are moved, that is to say towards the infrared. Therefore the emission curve also moves, in this case most of the emission would be in the infrared part, the visible radiation would be very small.

Furthermore, the total intensity of the semition decreases that the intensity depends on the fourth power of the temperature according to Stefan's law

           P = σ A eT⁴

Answer:

Pink - Pluto

Green - Mercury

Red - Mars

Black - Saturn

Blue - Neptune

Yellow - Jupiter

Orange - Jupiter

Milk Color - Venus

Explanation:

The galaxy is full of colors. There are various planets in the galaxy which are different colored. Their color is usually determined by the gases present there. The pink gases present near the Pluto makes Pluto appears to be of magenta or pink colored. The mercury is green colored because it reflects green rays. Mars is called the Red planet because of presence of Martin Rocks there.

Answer:

A and B

Explanation:

Answer:

B. wheelchair ramp

D. half-pipe at a skate park

Hope that helps!

Answer:

Ok, sabemos que la velocidad inicial de la pelota es 15m/s.

Desconocemos la posición inicial a la que es lanzada la pelota, pero vamos a suponer que es a una altura igual a cero, es decir, la pelota es lanzada al ras del suelo.

Una vez lanzada, la única fuerza actuando en la pelota es la gravitatoria, entonces la aceleración de la pelota es:

a = -g = -9.8m/s^2

El signo negativo es por que esta aceleración apunta hacia abajo.

Ahora, para la velocidad, necesitamos integrar sobre el tiempo.

v(t) = (-9.8m/s^2)*t + v0

donde v0 = 15m/s

v(t) = (-9.8m/s^2)*t + 15m/s.

De aca podemos obtener el tiempo en el que la pelota llega a la altura máxima, que es el punto donde la velocidad es igual a cero.

0 = (-9.8m/s^2)*t + 15m/s.

t = (15/9.8)s = 1.53 s

Ahora, para la ecuación de la posición integramos la ecuación de la velocidad sobre el tiempo:

p(t) = (1/2)(-9.8m/s^2)*t^2 + 15m/s*t + p0

donde p0 es la pocision inicial, pero arriba dijimos que era igual a cero, entonces la ecuación queda:

p(t) = (-4.5m/s^2)*t^2 + 15m/s*t

ahora reemplazamos t por el tiempo que encontramos antes, y descubrimos que:

p(1.53s) =  (-4.5m/s^2)*(1.53s)^2 + 15m/s*1.53s = 12.41m

La máxima altura que alcanza la pelota es 12.41 metros arriba del punto desde el que se la lanzo.

Ahora, el tiempo total que esta en el aire puede ser calculado de tal forma que la posición vuelva a ser cero, es decir, la pelota llega a la misma altura desde la que fue lanzada inicialmente (y es agarrada por la persona, podemos suponer)

Entonces:

p(t) = 0 =  (-4.5m/s^2)*t^2 + 15m/s*t

Ahora resolvemos la eq cuadrática, usando la eq. de Bhaskara:

[tex]t = \frac{-15 +- \sqrt{15^2 - 4*(-4.5)*0} }{-2*4.5} = \frac{-15 +-15}{-9.8}[/tex]

Entonces las soluciones son:

t = (-15 + 15)/-9.8 = 0s

t = (-15 - 15)/-9.8 = 3.06s

Tomamos la segunda solución, ya que la primera corresponde al tiempo inicial.

Entonces concluimos con que la pelota estuvo 3.06 segundos en el aire.

Answer:

17 m/s west

Explanation:

Runner 1 has velocity = 10 m/s west

runner 2 has velocity = 7 m/s east

From the frame of reference of runner 2, we can imagine runner 2 as standing still, and runner 1 moving away from him, towards the west with their combined velocity of

velocity = 10 m/s + 7 m/s = 17 m/s west

Answer:

17 m/s west

Explanation:

Hope this helps!