Which statement is part of Dalton's atomic theory?

What are the positive impacts of Genetically Modified Crops?

xeze [42]

Answer:

The crops will have the ability to be resistant to certain diseases

7 0

2 years ago

Read 2 more answers

A cake is removed from a 350◦F oven and placed on a cooling rack in a 70◦F room. After 30 minutes the cake is 200◦F. When will i

galben [10]

Answer:

350 F to 100 F it take approx 87.33 min

Explanation:

given data

oven = 350◦F

cooling rack = 70◦F

time = 30 min

cake = 200◦F

solution

we apply here Newtons law of cooling

$\frac{dT}{dt}$ = -k(T-Ta)

$\frac{dy}{dt}$ = $\frac{d}{dt}$ (T(t) -Ta)

= $\frac{dT}{dt} -\frac{dTa}{dt} =\frac{dT}{dt}$ = -k(T-Ta)

-ky $\frac{dy}{dt}$ = -ky

T(t) -Ta = (To -Ta) $e^{-kt}$ T(t) = Ta+ (To -Ta) $e^{-kt}$

put her value for time 30 min and T(t) = 200◦F and To =350◦F and Ta = 70◦F

so here

200 = 70 + ( 350 - 70 ) $e^{-k30}$

k = 0.025575

so here for T(t) = 100F

100 = 70 + ( 350 - 70 ) $e^{-0.025575*t}$

time = 87.33 min

so here 350 F to 100 F it take approx 87.33 min

5 0

3 years ago

La ecuación de la posición de una esferita está dada por: r(t)=(2.Cos(πt) i-3.Sen(πt) j) (m) ¿Cuál es la velocidad de la esferit

katovenus [111]

Answer:

v = (-4.44 i^ + 6.66 j^ ) m/s, a_average =( 0 i^ -2π j^) m/s²

Explanation:

The expression left corresponds to an oscillatory movement (MAS), the speed is defined by

v = dr / dt

the function of position

r = 2 cos πt i^ + 3 sin πt j^

let us note that it is a movement in two dimensions

let's perform the derivative

v = -2π sin πt i^ + 3π cos πt j^

we evaluate this expression for t = 0.25 s, remember that the angle is in radians

v = -2π sin (π 0.25) i^ + 3π cos (π 0.25) j^

v = (-4.44 i^ + 6.66 j^ ) m/s

To calculate the mean acceleration we use the expression

a = ( $v_{f} - v_{o}$ ) / Δt

indicates that the time is the first 3 s

we look for the initial velocity t = 0 s

v₀ = 0 i ^ + 3π j ^

we look for the fine velocity, t = 3 s

v_f = - 2π sin (π 3) + 3π cos (π 3) j ^

v_f = 0 i ^ - 3π j ^

we calculate the average acceleration

Δt = (3 -0) = 3 s

a_average = (0-0) / 3 i ^ + (-3π - 3π) / 3

a_average = (0 i ^ -2π j ^ ) m/s²

6 0

3 years ago

Which example is NOT a part of the electromagnetic spectrum?

Alekssandra [29.7K]

Electricity is NOT a part of electromagnetic spectrum.

An electromagnetic spectrum contains electromagnetic radiations arranged according to frequencies and wavelength.

<h2>Further Explanation </h2><h3>Electromagnetic waves </h3>

Electromagnetic waves are types of waves that do not require a material medium for transmission.
These waves are mostly transverse in nature, which means the direction of transmission is perpendicular to the direction of vibration of particles.
They include, light waves, radio waves, x-rays, infra-red, etc.

<h3>Electromagnetic spectrum </h3>

An electromagnetic wave shows electromagnetic waves arranged according to frequencies and wavelength.
Electromagnetic spectrum contains electromagnetic waves: Gamma rays, x-rays, Ultraviolet, Visible light, infra-red, microwaves, and radio waves.
The electromagnetic spectrum is divided into various sections based on wavelength, with gamma rays having the shortest wavelength and radio waves having the longest wavelength.
The part of the electromagnetic spectrum that we can see using our naked eyes is called the visible light spectrum.
In order of frequency, the radio waves have the lowest frequency while gamma rays have the largest frequency.

<h3>General characteristics of electromagnetic waves </h3>

They travel with the speed of light (3.0 x 10^8 m/s)
They possess energy that is given by; E =hf, where h is the plank’s constant and f is the frequency.
They are transverse in nature, and therefore, the wavelength is measured between successful crests or troughs.
They can travel through vacuum

Keywords: Electromagnetic spectrum, electromagnetic waves.

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