when a light beam emerges from water into air, the average light speed ____.

a. increases
b. decreases
c. remains the same
d. not provided

Answer:

Option 2

Explanation:

Given

Two 2-Ohm resistors are in series  and these two resistors are in parallel with a 4-Ohm resistor

Equivalent resistance of two resistors in series = R1 + R2 = 2+2 = 4 Ohm

Equivalent resistance of two 4 Ohm resistors is parallel =1/ (1/4 +1/4) = 2 Ohm

Voltage = 12 Volts.

Hence, current = V/R = 12/2 = 6 Amp

Option 2 is correct

Answer:

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( Here is solution)

Answer:

1 L = 1000 mL

125 mL = 125/1000 = 0.125 L

Answer:

0.125

Explanation:

divide by 1 000 to convert mL to liters

Complete Question

A 10 kg medicine ball is thrown at a velocity of 15 km/hr ( m/s) to a 50 kg skater who is at rest on the ice. The skater catches the ball and subsequently slides with the ball across the  ice.

Calculate the kinetic energy after collision(in joules).

Answer:

 [tex]K.E=70.23J[/tex]

Explanation:

From the question we are told that:

Mass of ball [tex]m_b=10kg[/tex]

Speed [tex]V_{b1}=15 km/hr ( m/s)[/tex]

            [tex]V_{b1} = 4.1667 m/s[/tex]

            [tex]V_{b1} = 4.1667 m/s[/tex]

Mass of Skater [tex]m_s=50kg[/tex]

Generally the equation for conservation of momentum is mathematically given by

  [tex]m_sV_{s1}+m_bV_{b1}=(m_s+m_b)V[/tex]

  [tex]V=\frac{m_sV_{s1}+m_bV_{b1}}{(m_s+m_b)}[/tex]

  [tex]V=\frac {50+10*4.1667}{(50+10)}[/tex]

  [tex]V=1.53m/s[/tex]

Generally the equation for  Kinetic energy is mathematically given by

 [tex]K.E=\frac{1}{2}(m_s+m_b)V^2[/tex]

 [tex]K.E=\frac{1}{2}(50+10)(1.53)^2[/tex]

 [tex]K.E=70.23J[/tex]

Therefore kinetic energy K.E after collision is given as

 [tex]K.E=70.23J[/tex]

Answer:

the energy when it reaches the ground is equal to the energy when the spring is compressed.

Explanation:

For this comparison let's use the conservation of energy theorem.

Starting point. Compressed spring

         Em₀ = K_e = ½ k x²

Final point. When the box hits the ground

         Em_f = K = ½ m v²

since friction is zero, energy is conserved

          Em₀ = Em_f

          1 / 2k x² = ½ m v²

          v = [tex]\sqrt{ \frac{k}{m} }[/tex]     x

Therefore, the energy when it reaches the ground is equal to the energy when the spring is compressed.

Based on the law of conservation of energy, the elastic potential energy of the system when the spring is fully compressed is equal to the kinetic energy of the system at the moment immediately before the box hits the ground.

The energy in a compressed spring is elastic potential energy given by the formula:

where

The kinetic energy of a body is the energy the body the has due to it's motion.

Kinetic energy, KE, is givenby the formula below:

From the law of conservation of energy, the total energy in a closed system is conserved.

Based on this law, all the energy in the compressed spring is converted to the kinetic energy of the box just before it reaches the ground.

Therefore, the elastic potential energy of the system when the spring is fully compressed is equal to the kinetic energy of the system at the moment immediately before the box hits the ground.

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Answer:

a)  

get mass of planet:  

ρ = M / V  

V = 4/3 * R_1^3  

M = ρ * V  

M = ρ * 4/3 * R_1^3  

equate force equations:

F = (GMm) / r^2     // r = R_2  

F = ma  

a = v^2/R_2  

F = m * (v^2/R_2)    

m * (v^2/R_2) = (GMm) / R_2^2  

plug in and solve v^2:  

m * (v^2/R_2) = (G * (ρ * 4/3 * R_1^3) *m) / R_2^2  

v^2 = (G * ρ * (4/3) * π * R_1^3) / R_2

put into kinetic energy equation:  

K = 1/2 * m * v^2  

K = 1/2 * m * (G * ρ * (4/3) * π * R_1^3) / R_2

B)

givens:  

U = -(GmM) / R_2

plug in mass of planet:  

U = -(G * m * ρ * 4/3 * R_1^3) / R_2

C)

use previous equations and do some algebra:

K/U = (1/2 * m * (G * ρ * (4/3) * π * R_1^3) / R_2) * -(R_2 / (G * m * ρ * 4/3 * R_1^3))  

K/U = -1/2

Pedro needs to control the variables such as volume of water and temperature during his experiment. So, option C.

The amount of water vapor in the air is known as humidity. The humidity will be high if there is a lot of water vapour in the atmosphere.

Water can evaporate even at very low temperatures, but as the temperature rises, the rate of evaporation increases.

More surface molecules per unit of volume may be able to escape from a substance with a larger surface area, so it will evaporate more quickly.

The control variables in an experiment are the variables that the experimenter intends to keep constant always so as to limit their effect on the measurements of the relationship between the dependent and the independent variable.

Therefore, in order to have a proper measurement of the effect of humidity on evaporation rate, other variables such as temperature, and the volume of the water in the experiment investigations which affect evaporation rate by the provision of heat, (temperature) and their heat capacity, the volume, etc. should be controlled.

Hence,

Pedro needs to control the variables such as volume of water and temperature during his experiment. So, option C.

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Answer:

[tex]56.5\ \text{s}[/tex]

[tex]21.13\ \text{m/s}[/tex]

Explanation:

v = Final velocity

u = Initial velocity

a = Acceleration

t = Time

s = Displacement

Here the kinematic equations of motion are used

[tex]v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{25-0}{2}\\\Rightarrow t=12.5\ \text{s}[/tex]

Time the car is at constant velocity is 39 s

Time the car is decelerating is 5 s

Total time the car is in motion is [tex]12.5+39+5=56.5\ \text{s}[/tex]

Distance traveled

[tex]v^2-u^2=2as\\\Rightarrow s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{25^2-0}{2\times 2}\\\Rightarrow s=156.25\ \text{m}[/tex]

[tex]s=vt\\\Rightarrow s=25\times 39\\\Rightarrow s=975\ \text{m}[/tex]

[tex]v=u+at\\\Rightarrow a=\dfrac{v-u}{t}\\\Rightarrow a=\dfrac{0-25}{5}\\\Rightarrow a=-5\ \text{m/s}^2[/tex]

[tex]s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{0-25^2}{2\times -5}\\\Rightarrow s=62.5\ \text{m}[/tex]

The total displacement of the car is [tex]156.25+975+62.5=1193.75\ \text{m}[/tex]

Average velocity is given by

[tex]\dfrac{\text{Total displacement}}{\text{Total time}}=\dfrac{1193.75}{56.5}=21.13\ \text{m/s}[/tex]

The average velocity of the car is [tex]21.13\ \text{m/s}[/tex].

Answer:

The work done by you on the two cart system is 2 N-m

Explanation:

Work done is the product of force and displacement.

W = F * D

Substituting the given values we get -

W =

[tex]4 * (0.17+0.33)\\= 2[/tex]

The work done by you on the two cart system is 2 N-m

Answer:

The correct answer is a

Explanation:

The speed of a sound wave depends on the square root of the modulus of compressibility and the density of the medium.

For the same medium, the speed of sound depends on the temperature of the fora

           v = [tex]v_o \ \sqrt{1 + \frac{T}{273} }[/tex]

Therefore, the different results that are obtained are due to changes in temperature. The correct answer is a

since this way it has the values ​​of the speed of sound for each temperature, for which it can compare with the results obtained from the trip.

102 m

Explanation:

The time 0.6 sec is the time it took for the sound to travel from the bat to the moth and back. So it took 0.3 sec for the sound to reach the moth. From the definition of speed, the distance of the moth d to the bat is given by

v = d/t ---> d = vt = (340 m/s)(0.3 sec) = 102 m

Answer:

The correct answer is "53.15 days".

Explanation:

Given that:

Half life of [tex]131_{I}[/tex],

[tex]T_{\frac{1}{2} }= 8 \ days[/tex]

To find t when R will be "1%" of [tex]R_o[/tex], then

⇒ [tex]R=\frac{1}{100}R_o[/tex]

As we know,

⇒ [tex]R=R_o e^{-\lambda t}[/tex]

or,

∴ [tex]e^{\lambda t}=\frac{R_o}{R}[/tex]

By putting the values, we get

        [tex]=\frac{R_o}{\frac{R}{100} }[/tex]

        [tex]=100[/tex]

We know that,

Decay constant, [tex]\lambda = \frac{ln2}{T_{\frac{1}{2} }}[/tex]

hence,

⇒ [tex]\lambda t=ln100[/tex]

     [tex]t=\frac{ln100}{\lambda}[/tex]

        [tex]=\frac{ln100}{\frac{ln2}{8} }[/tex]

        [tex]=53.15 \ days[/tex]  

Answer:

Biodiversity decline continues due to a rapidly expanding human population. Habitat is damaged in order to meet growing needs for agriculture, urban development, water and materials. Fish, wildlife and plants are overharvested, despite mounting evidence that many harvesting practices are unsustainable.

For the  pendulum taken to the moon, The frequency change that would occur is mathematically given as

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

Generally, the equation for the Time period  is mathematically given as

[tex]T=2\pi\sqrt{L/g}[/tex]

Therefore

[tex]\frac{Fmoon}{Fearth}=\frac{\sqrt{g/6L}}{\sqrt{g/6L}}\\\\\frac{Fmoon}{Fearth}=\sqrt{1/6}[/tex]

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

In conclusion, The frequency change

[tex]\frac{Fmoon}{Fearth}=0.408[/tex]

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Answer:

.408

Explanation:

Answer:

The final angular velocity is rev/s is 0.293 rev/s.

Explanation:

Given;

mass of the merry-go-round, m₁ = 120 kg

radius of the merry-go-round, r = 1.8 m

initial angular velocity, ω = 0.4 rev/s

mass of the child, m₂ = 22 kg

Apply the principle of conservation angular momentum to determine the final angular velocity;

[tex]I_i= I_f\\\\\frac{1}{2} m_1r^2 \omega _i = \frac{1}{2} m_1r^2 \omega _f + m_2r^2 \omega _f\\\\ \frac{1}{2} m_1r^2 \omega _i =( \frac{1}{2} m_1r^2 + m_2r^2 )\omega _f\\\\\omega _f = \frac{ \frac{1}{2} m_1r^2 \omega _i}{\frac{1}{2} m_1r^2 + m_2r^2} \\\\\omega _f = \frac{ \frac{1}{2} m_1 \omega _i}{\frac{1}{2} m_1 + m_2}\\\\\omega _f = \frac{0.5 \ \times \ 120\ kg \ \times \ 0.4\ rev/s}{0.5 \ \times 120\ kg \ \ + \ \ 22 \ kg} \\\\\omega _f = 0.293 \ rev/s\\[/tex]

Therefore, the final angular velocity is rev/s is 0.293 rev/s.

Answer:

[tex]380697.33\ \text{N/m}[/tex]

[tex]0.138\ \text{m}[/tex]

Explanation:

m = Mass rocket = 1070 kg

v = Velocity of rocket = 3.75 m/s

a = Acceleration of rocket = 5g

g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]

The energy balance of the system is given by

[tex]\dfrac{1}{2}kx^2=\dfrac{1}{2}mv^2\\\Rightarrow kx=\dfrac{mv^2}{x}\\\Rightarrow kx=\dfrac{1070\times 3.75^2}{x}\\\Rightarrow kx=\dfrac{7250}{x}[/tex]

The force balance of the system is given by

[tex]ma=kx\\\Rightarrow m5g=\dfrac{7250}{x}\\\Rightarrow x=\dfrac{7250}{1070\times 5\times 9.81}\\\Rightarrow x=0.138\ \text{m}[/tex]

The distance the spring must be compressed is [tex]0.138\ \text{m}[/tex]

[tex]k=\dfrac{7250}{x^2}\\\Rightarrow k=\dfrac{7250}{0.138^2}\\\Rightarrow k=380697.33\ \text{N/m}[/tex]

The force constant of the spring is [tex]380697.33\ \text{N/m}[/tex].

2 bar magnets top to bottom with their long axes vertical, the top one with red S on top and blue N on bottom and the bottom magnet with red S on top and blue N on bottom. this diagram shows magnets that will attract each other. Hence option D is correct.

A permanent magnet is an item constructed of magnetised material that generates its own persistent magnetic field. A refrigerator magnet, for example, is commonly used to hold notes on a refrigerator door. Ferromagnetic (or ferrimagnetic) materials are those that can be magnetised and are strongly attracted to a magnet. These include the elements iron, nickel, and cobalt, as well as their alloys, some rare-earth metal alloys, and naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones that are strongly attracted to a magnet and are widely thought to be magnetic, all other substances respond weakly to a magnetic field via one of many different forms of magnetism.

Hence option D is correct.

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Answer:

The tension in string will be "3.62 N".

Explanation:

The given values are:

Length of string:

l = 3 ft

or,

 = 0.9144 m

frequency,

f = 60 Hz

Weight,

= 0.096 lb

or,

= 0.0435 kgm/s²

Now,

The mass will be:

= [tex]\frac{0.0435}{9.8}[/tex]

= [tex]0.0044 \ kg[/tex]

As we know,

⇒  [tex]\lambda=\frac{2L}{n}[/tex]

On substituting the values, we get

⇒     [tex]=\frac{2\times 0.9144}{4}[/tex]

⇒     [tex]=0.4572 \ m[/tex]

or,

⇒  [tex]v=f \lambda[/tex]

⇒      [tex]=0.4572\times 60[/tex]

⇒      [tex]=27.432 \ m/s[/tex]

Now,

⇒  [tex]v=\sqrt{\frac{T}{\mu} }[/tex]

or,

⇒  [tex]T=\frac{m}{l}\times v^2[/tex]

On putting the above given values, we get

⇒      [tex]=\frac{0.0044}{0.9144}\times (27.432)^2[/tex]

⇒      [tex]=\frac{752.51\times 0.0044}{0.9144}[/tex]

⇒      [tex]=3.62 \ N[/tex]

Answer:

The balloon will collapse

Explanation:

When air is removed from the bell jar, the balloon will collapse if the internal pressure from the balloon does not balance the atmospheric pressure from the surroundings.

Answer:

I would say d I had the same question yesterday and I got it correct so hope that helps

Answer:

.0000004

Explanation:

The mass of a brick with a volume of 0.0006 m³ and a density of 1600 kg/m³ is 0.96kg.

The mass of a substance can be calculated by multiplying the density of the substance by its volume. That is;

Mass = density × volume

According to this question, the density of brick is 1,600 kg/m3 and it has a volume of 0.0006m³. The mass is calculated as follows:

Mass = 0.0006 × 1600

Mass = 0.96kg

Therefore, the mass of a brick with a volume of 0.0006m³ and a density of 1600 kg/m³ is 0.96kg.

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Answer:

 m₂ = 4 kg

Explanation:

The moment of inertia is defined by

         I = ∫ r² dm

for bodies with high symmetry it is tabulated, for a spherical shell

        I = 2/3 m r²

in this case the first sphere has a radius of r₁ = 2m and a mass of m₁ = 1 kg, the second sphere has a radius r₂ = 1m.

They ask what is the masses of the second spherical shell so that the moment of inertia of the two is the same.

        I₁ = ⅔ m₁ r₁²

        I₂ = ⅔ m₂ r₂²

They ask that the two moments have been equal

        I₁ = I₂

        ⅔ m₁ r₁² = ⅔ m₂ r₂²

         m₂ = (r₁ / r₂) ² m₁

let's calculate

         m₂ = (2/1) ² 1

         m₂ = 4 kg

Answer:

[tex]\mu=41.5\textdegree[/tex]

Explanation:

From the question we are told that:

Water index of refraction [tex]i_w=1.33[/tex]

Glass index of refraction [tex]i_g=1.50[/tex]

Generally the equation for Brewster's law is mathematically given by

 [tex]\theta=tan^{-1}(\frac{i_g}{i_w})[/tex]

 [tex]\theta=tan^{-1}(\frac{1.50}{1.33})[/tex]

 [tex]\theta=48.44 \textdegree[/tex]

Therefore Angle of incident to plane  \mu (normal at 90 degree to the surface)

 [tex]\mu=90\textdegree-\theta[/tex]

 [tex]\mu=90\textdegree-48.44\textdegree[/tex]

 [tex]\mu=41.5\textdegree[/tex]

If ' c ' is the speed of light, then the formula for it is . . .

c = 299,792,458 meters per second

Answer:

Definimos momento como el producto entre la masa y la velocidad

P = m*v

(tener en cuenta que la velocidad es un vector, por lo que el momento también será un vector)

Sabemos que el peso de la paca de heno es 175N, y el peso es masa por aceleración gravitatoria, entonces.

Peso = m*9.8m/s^2 = 175N

m = (175N)/(9.8m/s^2) = 17.9 kg

Ahora debemos calcular la velocidad de la paca justo antes de tocar el suelo.

Sabemos que la velocidad horizontal será la misma que tenía el avión, que es:

Vx = 36m/s

Mientras que para la velocidad vertical, usamos la conservación de la energía:

E = U + K

Apenas se suelta la caja, esta tiene velocidad cero, entonces su energía cinética será cero y la caja solo tendrá energía potencial (Si bien la caja tiene velocidad horizontal en este punto, por la superposición lineal podemos separar el problema en un caso horizontal y en un caso vertical, y en el caso vertical no hay velocidad inicial)

Entonces al principio solo hay energía potencial:

U = m*g*h

donde:

m = masa

g = aceleración gravitatoria

h = altura  

Sabemos que la altura inicial es 60m, entonces la energía potencial es:

U = 175N*60m = 10,500 N

Cuando la paca esta próxima a golpear el suelo, la altura h tiende a cero, por lo que la energía potencial se hace cero, y en este punto solo tendremos energía cinética, entonces:

10,500N = (m/2)*v^2

De acá podemos despejar la velocidad vertical justo antes de golpear el suelo.

√(10,500N*(2/ 17.9 kg)) = 34.25 m/s

La velocidad vertical es 34.25 m/s

Entonces el vector velocidad se podrá escribir como:

V = (36 m/s, -34.25 m/s)

Donde el signo menos en la velocidad vertical es porque la velocidad vertical es hacia abajo.

Reemplazando esto en la ecuación del momento obtenemos:

P = 17.9kg*(36 m/s, -34.25 m/s)  

P = (644.4 N, -613.075 N)

Answer:

The depth of the diver is 28.01 m

Explanation:

Given;

density of the seawater, ρ = 1,015 kg/m³

standard sea level pressure, P₀ = 1.0 atm = 101,325 Pa

the final reading of her pressure, P₁ = 3.75 atm = 379968.75 Pa

acceleration due to gravity, g = 9.8 m/s²

Let the depth she was diving at the final pressure = h

This depth is calculated as;

P₁ = P₀  +  ρgh

P₁ - P₀ =  ρgh

[tex]h = \frac{ P_1 \ - \ P_o}{\rho g} = \frac{379968.75 \ - \ 101325}{1015 \ \times \ 9.8} = 28.01 \ m[/tex]

Therefore, the depth of the diver is 28.01 m

Answer: a different one is a.b.c

Explanation: still for ape.x

The correct order to determine the age of the an object using carbon-14 is C, A, B. Thus, option D is correct.

The half-life time is defined as the time taken by the radioactive element to reduce one half of its initial value. It is denoted by t(1/2).

To measure the age of an object, a radioactive isotope called carbon-14 is used. The half-life of carbon-14 is 5,730 years. All the objects in the universe consumes carbon  in their lifetime and hence, carbon-14 is used to measure the age of the objects.

The process of determining the age of objects using carbon-14 is called Radiocarbon dating. All living organisms consume carbon in means of food and from atmosphere and when the plant and animals dies, the radioactive carbon atoms start decaying.

When it starts decaying, by using Carbon-14 the age of an object is calculated. The age is estimated by measuring the amount of carbon-14 present in the sample and comparing this carbon with the reference Carbon-14 isotope.

The amount of carbon in  preserved plants is identified by:

f(t) = 10e {₋ct}  

t = time in years when the plant dies( t= 0)

c = the amount of carbon-14 remaining in preserved plants.

The steps include to find the age of an object is :

1. Use the number of half-lives that have passed to determine the age of the object.

2. Use the half-life of carbon-14 to determine the number of half-lives that have passed.

3.Measure the ratio of parent nuclei to daughter nuclei.

Hence, from these steps the age of an object is determined. Therefore the correct solution is D) C, A, B.

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Answer:

Explanation:

In equilibrium , weight of mug is equal to restoring force .

mg = kx where m is mass of mug , k is spring constant and x is extension .

k / m = g / x = 9.8 ms⁻² / .025 m

= 392

frequency of oscillation n = [tex]\frac{1}{2\pi}\sqrt{\frac{k}{m} }[/tex]

[tex]n=\frac{1}{2\pi}\sqrt{392 }[/tex]

= 4.46 per second.