Humans sleep in cycles, usually two or three cycles per night. There is a point in each cycle when waking up will leave the sleeper feeling the most rested and refreshed.

After learning about this, a computer programmer designed a new smartphone alarm clock. This new alarm clock uses sensors in the smartphone to detect the sleeper’s motion and determine when the sleeper has reached the best point in the sleep cycle at which to wake up. The app can be downloaded onto any smartphone. Most users who download this app find that it does not help them wake up feeling more refreshed, but they are willing to try improved products in the future.

Which criterion did this sleep cycle alarm clock fail to meet?

It did not solve the problem.
It was not cost effective enough.
It was not readily available.
It was not safe for most users.

Answer:

values of gravitational force and gravitational constant become same or equal when product of masses involved equals the square of distance between them

Explanation:

Answer:

A thick layer of material with a low thermal conductivity reduces the rate of heat transfer from the ceiling into the roof space.

Answer:

13 atoms

Explanation:

Look at the subscripts.

“Mg₃” means that there are 3 magnesium atoms; “PO₄” means that there is 1 phosphorus atom and 4 oxygen atoms. But note that the PO₄ group has a subscript too: 2. This multiplies the atom count by 2, so you have 2 phosphorus atoms and 8 oxygen atoms.

3 + 2 + 8 = 13

(hope this helps can i plz have brainlist :D hehe)

There are total 26 atoms in 2Mg₃(PO₄)₂ compound. in one Mg₃(PO₄)₂, there are 13 atoms. Therefore, in 2 Mg₃(PO₄)₂ units, there are 26 atoms  in total.

A chemical formula is used identify a compound and to indicate chemical composition. The molecular formula of a compound is written based on the chemical symbol of each constituent atoms and their numbers.

The number of the atoms of each elements are represented as subscripts for each elemental symbol. In the given compound Mg₃(PO₄)₂, one unit of the compound contain 3 Mg atoms, and 2 PO₄ units means 2 P and 8 oxygen atoms. Hence there are 13 atoms in one unit.

There are 2 such units of this compound. Therefore, the total number of atoms present in 2 units Mg₃(PO₄)₂ compound is 13×2 =26.

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Answer:

980 is the expected number of nondefective lightbulbs in a random sampling of 1,000 bulbs

Explanation:

If the company claims is right, this is the task that should be done

Lightbulbs = 1,000 * 0.98 = 980

Therefore, 980 working bulbs is expected out of a sample of 1,000 lightbulbs

Answer:

I think it's A C and D sry if I'm wrong UwU

Answer:

The two types of forces are related; a moving magnet can make electrical charges move, cause an electric current, and in turn cause magnetism. ... Objects that have the same charge, both positive or both negative, repel each other, and those with opposite charges attract each other.

Explanation:

Answer:

Explanation:

1- incident ray

2- the substance through which the wave travels

Answer: the incident ray(the incident ray is the ray striking the mirror at the point of incidence while the refracted ray is the ray leaving the mirror)

The substance through which the ray or wave travels.

Answer:

His average speed is 980 units

Explanation:

convex mirror and concave lens

Answer:

sodium chloride

Explanation:

Sodium chloride is an ionic compound. The ions of the sodium chloride compound is sodium ion and chloride ion.  The sodium ion is cation while the chloride ion is an anion. Sodium chloride is a very stable compound because of the mutual attraction of oppositely charged ions.

Answer: 29828 watts

Explanation: hope that helped bro

Answer:

Explanation:

1/Rtotal = 1/r1 +1/r2 +1/r3

1/Rtotal = 1/44 + 1/44 + 1/44

1/Rtotal = 3 /44

1/Rtotal = 0.0681818182

1/0.0681818182 = Rtotal

14.66666666666666666 = Rtotal

14 [tex]\frac{2}{3}[/tex] ohms = Rtotal

Answer:

a) R = 172.82 m, 5.3 north of east    b)   v = (0.24 ± 0.01) m / s

Explanation:

a) the displacement is a vector, so the easiest method to lock is looking for each component

let's start decomposing the vectors

 x₁ = - 160 m

second shift

angle 45 south of east

     cos (-45) = x₂ / d₂

     sin (-45) = y₂ / d₂

     x₂ = d₂ cos 45

     y₂ = -d₂ sin 45

     x₂ = 180 cos 45 = 127.28 m

     y₂ = -180 sin 45 = - 127.28 m

third shift

      cos 35 = x₃ / d₃

      sin 35 = y₃ / d₃

      x₃ = d₃ cos 35

      y₃ = d₃ sin 35

      x₃ = 250 cos 35 = 204.79 m

      y₃ = 250 sin 35 = 143.39 m ₃

X axis

       x_total = x₁ + x₂ + x₃

       x_total = -160 +127.28 +204.79

       x_total = 172.07 m

Y axis  

      y_total = y₁ + y₂ + y₃

      y_total = 0 - 127.28 + 143.39

      y_total = 16.11 m

to compose the displacement we use the Pythagorean theorem

      R = [tex]\sqrt{x^2 +y^2}[/tex]

      R = [tex]\sqrt{172.07^2 + 16.11^2 }[/tex]

      R = 172.82 m

in angle is

      tan θ = y_total / x_total

      ten θ = 16.11 / 172.07 = 0.0936

      θ = tan⁻¹ 0.0936

       θ = 5.3

angle is 5.3 north of east

b) the error in the distance is 5%,

               e% = ΔR/R  100

               ΔR = e% R / 100

               ΔR = 5 172.82 / 100

               ΔR = 8.6 m

the time error Dt = 20 s

We calculate the speed and this we calculate the error

      v = R / t

      v = 172.82 / 12 60

      v = 0.240027 m / s

the error in this magnitude is

      Δv = [tex]\frac{dv}{dR} \ \Delta R + \frac{dv}{dt} \ \Delta t[/tex]

       Δv = [tex]\frac{1}{t} \ \Delta R + \frac{R}{t^2 } \ \Delta t[/tex]

         Δv = [tex]\frac{ 8.6}{720} + \frac{172.82 \ 20}{720^2 }[/tex]

         Δv = 0.013 m / s

the measurement result is

         v = (0.24 ± 0.01) m / s

Answer:

[tex]W=17085KJ[/tex]

Explanation:

From the question we are told that:

Height [tex]H=16m[/tex]

Radius [tex]R=3[/tex]

Height of water [tex]H_w=9m[/tex]

Gravity [tex]g=9.8m/s[/tex]

Density of water [tex]\rho=1000kg/m^3[/tex]

Generally the equation for Volume of water is mathematically given by

 [tex]dv=\pi*r^2dy[/tex]

 [tex]dv=\frac{\piR^2}{H^2}(H-y)^2dy[/tex]

Where

   y is a random height taken to define dv

Generally the equation for Work done to pump water is mathematically given by

 [tex]dw=(pdv)g (H-y)[/tex]

Substituting dv

 [tex]dw=(p(=\frac{\piR^2}{H^2}(H-y)^2dy))g (H-y)[/tex]

 [tex]dw=\frac{\rho*g*R^2}{H^2}(H-y)^3dy[/tex]

Therefore

 [tex]W=\int dw[/tex]

 [tex]W=\int(\frac{\rho*g*R^2}{H^2}(H-y)^3)dy[/tex]

 [tex]W=\rho*g*R^2}{H^2}\int((H-y)^3)dy)[/tex]

 [tex]W=\frac{1000*9.8*3.142*3^2}{9^2}[((9-y)^3)}^9_0[/tex]

 [tex]W=3420.84*0.25[2401-65536][/tex]

 [tex]W=17084965.5J[/tex]

 [tex]W=17085KJ[/tex]

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Answer:

tire marks are due to the increase in thermal energy

Explanation:

When a tire is spinning at a given speed when the brakes are applied hard, the friction between the tire's particulate and the ground surface is high enough that some tire particles are transferred to the ground.

This is reflected in the heat transfer from the tire to the ground.

Consequently, tire marks are due to the increase in thermal energy and the change in the friction force of the tire.

Answer:

Going super fast and stopping abruptly causes friction which causes heat thus it melts the surface of the tire.

Explanation:

This is example answer for edmentum :)

Answer:

Under normal conditions – closed circuit – these contacts are touching each other, allowing the flow of electric current. These moving contacts are held together thanks to mechanical pressure exerted by another mechanism – a spring or compressed air

Answer:

According to Lorentz transformation, the time observed of by objects moving in different reference frames are related to their velocity of motion and the speed of light

The time measured by Sarah who is located at the source of the signal and the center of the explosion is different from the time measured by Adam who is moving relative to Sarah and observes the signals moving at different speeds and therefore observes the buildings blow up not immediately but at different times

Explanation:

The time and space dilation equations are given as follows;

[tex]\Delta t = \dfrac{\Delta t'}{\sqrt{1 - \dfrac{v^2}{c^2} } }[/tex]

[tex]L = L' \times \sqrt{1 - \dfrac{v^2}{c^2} }[/tex]

Where;

Δt' = The time measured by Adam

Δt = The time measured by Sarah

L' = The distance measured by Adam

L= The distance measured by Sarah

v = The velocity at which Adam is moving

Let 'u' represent the speed of the signals

Given that Adam is traveling in between the two clock towers such that one signal is moving in the opposite direction towards him while the other signal moves in the his direction, by relativistic velocity addition, we have;

The velocity with which Adam observes the signal coming towards him, v' is given as follows;

v'' = (v + u)/(1 + v·u/c²)

∴ v'' > v

For the signal moving in the direction of Adam, we have;

v''' = (v - u)/(1 - v·u/c²)

v''' < v

Therefore, we have;

The time it takes the light to reach Adam from the furthest Tower which he passes as he is flies past Sarah in the middle, Δt'' is given as follows;

[tex]\Delta t'' = {\Delta t'} \times {\sqrt{1 - \dfrac{v''^2}{c^2} } }[/tex]

For the closer tower which Adam approaches, we have;

[tex]\Delta t''' = {\Delta t'} \times {\sqrt{1 - \dfrac{v'''^2}{c^2} } }[/tex]

Given that v'' > v''', therefore Δt'' < Δt''' and the time the light from the furthest building is seen first by Adam before the light from the closer building.

Answer: Photoelectric effect

Explanation:

Answer:

position 1

Explanation:

in position 2 and three it would have less energy cause there is less force being exerted to give it that push, but at the end position and the first position there is going to be more force and energy behind the ball.

heating of anything increases the kinetic energy of its molecules, so the molecules will move faster.

A helium balloon's temperature is raised by 1°C. This will cause molecules to move faster.

The temperature has an impact on this average kinetic (motional) energy. Their average kinetic energy likewise rises when gas molecules warm up.

As a result, they travel more quickly and collide more frequently and violently inside the balloon. The temperature has an impact on the hot air balloon's internal pressure. The molecules move more quickly and forcefully against the interior wall of the balloon as they warm up.

A region of the balloon is subjected to more force due to the gas particles' greater velocity, which raises the pressure there.

Therefore, the temperature of a helium balloon is increased by 1°C. Molecules will move more quickly as a result.

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Answer:

A thermo flask has a cork which prevents heat loss by conduction.

It also has vacuum which prevents heat loss by convection.

Option A: The air molecule moves from the girl's mouth to the ear of her friend

Answer:

a)

there r two types of motion, uniform and non-uniform

uniform means equal distance travelled at equal intervals of time

and non-uniform is exactly the opposite.

b)

quantities which can be represented by magnitude along r called scalar quantities such as speed.

quantities which need magnitude along with direction r called vector quantities such as velocity.

c)

velocity=10m/s

acceleration = u-v/s i.e initial final velocity - initial velocity upon time

acceleration= 0.2m/s sq

time= 30s

10 = displacement/time

10 = x/30

10 = 300

Answer is 300 meters - distance/displacement.

Answer:

[tex]\huge\boxed{\sf P.E. = 240\ MJ}[/tex]

[tex]\huge\boxed{\sf K.E. = 19.6\ MJ}[/tex]

Explanation:

Given:

Mass = m = 200,000 kg

Vertical Distance = h = 120 m

Speed = v = 14 m/s

Acceleration due to gravity = g = 10 m/s²

Required:

1) Gravitational Potential Energy = P.E = ?

2) Kinetic Energy = K.E. = ?

Formula:

1) P.E. = mgh

2) K.E. = [tex]\displaystyle \frac{1}{2} mv^2[/tex]

Solution:

1) P.E. = (200,000)(10)(120)

P.E. = 240,000,000 Joules

P.E. = 240 Mega Joules

P.E. = 240 MJ

2) K.E. = 1/2 (200000)(14)^2

K.E. = (100000)(196)

K.E. = 19,600,000 Joules

K.E. = 19.6 MJ

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer:

A). The faster an object moves, the more stretched time becomes.    

Explanation:

'Time dilation' is described as the 'slowing of the passage of time experienced by objects in motion relative to an observer that is measurable only at the relative speeds.' As per this particular relativity theory, the observer witnesses an elongated time with reference to the other setting. This reduction in speed of time(slowing down) becomes more clear and evident in the case of an object moving briskly near to the light's speed. Thus, option A is the correct answer.

Answer:

Explanation:

Work = Force times displacement. Therefore,

W = 3150(75.5) so

W = 238000 N*m

Answer:

Similitudes y diferencias entre los músculos de los peces y los de los animales terrestres.

Explicación:

Los músculos de los peces se diferencian del músculo de los animales terrestres porque los peces tienen músculos rojos, rosados y blancos. También tienen tejido muscular de pescado que se compone de músculo estriado al igual que el músculo de los animales terrestres. La mayor parte del tejido muscular de los peces es de color blanco, pero muchos peces también tienen una cierta cantidad de tejido oscuro de color marrón o rojizo. El músculo oscuro se encuentra justo debajo de la piel a lo largo del costado del cuerpo.