a solid weighs 20gf in air and 18 gf in water.Find the specific gravity of the solid. Please show your work.
Answer: It is given that A body weighs 20gf in air and 18. 0gf in water. Hence, the answer X-3 = 7.
Which reverses the flow of current through
an electric motor?
Answer:
a commutator
Explanation:
A 1000 kg car travels on a highway with a speed of 30 m/s. The driver sees a roadblock and applies the brakes, which provide a
constant braking force of 4 kN. What is the acceleration of the car?
A. 4 m/s
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
Una persona lanza una pelota hacia arriba con una velocidad de 15 metros por segundo. - Calcule: o Altura máxima que alcanza la pelota o Tiempo en el aire.
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.
70kg man runs up a flight of staurs in 4 sec . The vertical height of the stairs is 4.5 m . Calculate his power
Answer:
771.75 wattExplanation:
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!!
Runner 1 has a velocity of 10 m/s west. Runner 2 has a velocity of 7 m/s east. From the frame of reference of runner 2, what is the velocity of runner 1? A.17 m/s east. B.3 m/s east. C.17 m/s west. D.3 m/s west
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!
an attempt to estimate the height of a tree the Shadow of an upright metre rule was found to be 25 cm and the length of the Shadow of the tree was 7 m what is the height of the tree
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.
This is a form of energy representing the motion of the molecules which make up an object. A. Thermal Energy B. Kinetic Energy C. Gravitational Potential Energy D. Chemical Potential Energy
Answer:
Kinetic energy.
Explanation:
There are many kinds of energy. Some of them are kinetic energy, potential energy, thermal energy etc. The energy that shows the motion of the object is called its kinetic energy.Also, the sum of kinetic energy and the gravitational potential energy is called mechanical energy. Out of the given options, kinetic energy is the form of energy that represents the motion of the molecules which make up an object. Hence, the correct option is (B).Can someone please help me?
An alien spaceship is 650 m above the ground and moving at a constant velocity of 175 m/s upwards.
How high above the ground is the ship after 5 seconds?
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.
Which of the following is a device that uses an inclined plane?
Check all that apply.
A. knife
B. wheelchair ramp
C. bicycle
D. half-pipe at a skate park
Answer:
A and B
Explanation:
Answer:
B. wheelchair ramp
D. half-pipe at a skate park
Hope that helps!
9) Of all the types of light the Sun gives off, it emits the greatest amount of light at visible wavelengths of light. If the Sun were to cool off dramatically and as a result start giving off mainly light at wavelengths longer than visible light, how would the frequency, energy, and speed of this light given off by the Sun also be different? Explain your reasoning.
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
On a horizontal frictionless surface a mass M is attached to two light elastic strings both having length l and both made of the same material. The mass is displaced by a small displacement Δy such that equal tensions T exist in the two strings, as shown in the figure. The mass is released and begins to oscillate back and forth. Assume that the displacement is small enough so that the tensions do not change appreciably. (a) Show that the restoring force on the mass can be given by F = -(2T∆y)/l (for small angles) (b) Derive an expression for the frequency of oscillation.
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]
A uniform string of length 10.0 m and weight 0.32 N is attached to the ceiling. A weight of 1.00 kN hangs from its lower end. The lower end of the string is suddenly displaced horizontally. How long does it take the resulting wave pulse to travel to the upper end
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
Two charged objects are separated by some distance. The charge on the first object is greater than the charge on the second object. How do the forces that the two objects exert on each other compare
Even though the charge on the first object is greater, the forces that the two objects exert on each other are equal
A skateboarder rides down the street. When his feet push down on the
skateboard, what is the reaction force?
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:
We have seen that starlight passing through the interstellar medium is dimmed and reddened. Look at the photo of a sunset on Earth. The Sun’s light also appears reddish at sunset. Given your understanding of the reddening of starlight, why do you think sunsets appear red?
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 .
Suppose a point charge is located at the center of a spherical surface. The electric field at the surface of the sphere and the total flux through the sphere are determined. Now the radius of the sphere is halved. What happens to the flux through the sphere and the magnitude of the electric field
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.
What does Electromagnetic induction mean?
Transformers are of two types: Step up and Step down.
What is step up transformer?
What is step down transformer?
What is the difference between them?
Please I really need help.
Don't answer the question for points if you don't know what it means!
Answer:
Electromagnetic introduction is the production of an electromotive force (voltage) across an electrical conductor in a changing magnetic field.
Step up transformers is a transformer in which the output (secondary) voltage is greater than its input (primary) voltage is called a step-up transformer. The step-up transformer decreases the output current for keeping the input and output power of the system equal.
Step down transformer is a transformer in which the output (secondary) voltage is less than its input (primary) voltage is called a step-down transformer. The number of turns on the primary of the transformer is greater than the turn on the secondary of the transformer.
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.
Pink
Green
Red
Black
Blue
Yellow
Orange
"Milk colour"
what planet colour is that ??
thankyou for helping
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.
What happens when white light shines through a translucent, red, glass window? a) All colors of light except red are transmitted through the glass. b) Red light is transmitted through and reflected by the glass c) Red light is absorbed by the glass d) all colors except red are reflected by the glass
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.
What happens when white light shines through red glass?Red light emerges from the other side of a white light source that has been passed through a red filter. This is so that only red light can pass through the red filter. The spectrum's other colors (wavelengths) are absorbed. Similar to this, a green filter only lets through green light.White light is colorless light that contains all the wavelengths of the visible spectrum. Only specific wavelengths of white light are filtered through transparent or translucent things.Through a colorful glass, white light shines through. Except for the color it is shining through, all light wavelengths are absorbed by the glass.Therefore, if the red light passes through a translucent, red, glass, window, all the wavelengths are absorbed 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
The large-scale distribution of galaxies in the universe reveals Group of answer choices a smooth, continuous, and homogenous arrangement of clusters large voids, with most of the galaxies lying in filaments and sheets a large supercluster at the center of universe a central void with walls of galaxies at the edge of the universe
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!
Fig.4.1
The switch S is closed for a period of 5.0 minutes. Calculate
(a)
the current through each resistor.
чре
(b)
the current through the battery.
rad
rad
(c)
the total charge which passes through the battery.
ma
(d)
the energy supplied by the battery.
ars
Answer:
A
Explanation:
Suppose a 50.0 g block of silver (specific heat = 0.2350 J/g·°C) at 100.°C is placed in contact with a 50.0 g block of iron (specific heat = 0.4494 J/g·°C) at 0.00°C, and the two blocks are insulated from the rest of the universe. The final temperature of the two blocks will be:
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
A disk-shaped merry-go-round of radius 3.03 mand mass 145 kg rotates freely with an angular speed of 0.681 rev/s . A 65.4 kg person running tangential to the rim of the merry-go-round at 3.41 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the same direction as the merry-go-round's rim. What is the final angular speed of the merry-go-round?
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
Which of the following object is in dynamic equilibrium?
Answer:
A car driving in a straight line 20 m/s
Explanation:
ayepecks silly
explain why energy is important to us?
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.
What is the acceleration of a cabinet of mass 45 kilograms if Jake and Ted push it by applying horizontal force of 25 newtons and 18 newtons respectively in the same direction
Answer:
[tex]a=0.96\ m/s^2[/tex]
Explanation:
Given that,
Mass of cabinet, m = 45 kg
Two horizontal force of 25 newtons and 18 newtons respectively in the same direction.
When the forces are acting in same direction, the net force is equal to the sum of forces i.e.
F = 25 N + 18 N = 43 N
Let a is the aceleration of the cabinet
So,
F = ma
[tex]a=\dfrac{F}{m}\\\\a=\dfrac{43}{45}\\\\a=0.96\ m/s^2[/tex]
So, the acceleration of the cabinet is [tex]0.96\ m/s^2[/tex].
Ozone molecules in the stratosphere absorb much of the harmful radiation from the sun. How many ozone molecules are present in 2.00 L of air under the stratospheric ozone conditions of 275 K temperature and 1.89 × 10−3 atm pressure?
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.
a 15kg television sits on a shelf at a height of 0.3 m how much gravitational potential energy is added to the television when it is lifted to a shelf of height 1.0m?
Answer:
103 JoulesExplanation:
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
Unpolarized light is incident onto three polarizers with their transmission axes oriented in such a way that the first and the last make a 39 angle between them, and the middle one makes the same angle with the first and the last one. Find the percentage of the incident light which passes through these three polarizers.
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