The rate at which the earth's surface loses heat and keeps earth temperature at which living things can survive

Starting from zero, the electric current takes 2 seconds to reach half its maximum possible value in an RL circuit with a resist

Leno4ka [110]

Answer:

time=4s

Explanation:

we know that in a RL circuit with a resistance R, an inductance L and a battery of emf E, the current (i) will vary in following fashion

$i(t)=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$ , where $i$ max= $\frac{E}{R}$

Given that, at i(2)= $\frac{imax}{2} =\frac{E}{2R}$

⇒ $\frac{E}{2R}=\frac{E}{R}(1-e^\frac{-2}{\frac{L}{R}})$

⇒ $\frac{1}{2}=1-e^\frac{-2}{\frac{L}{R}}$

⇒ $\frac{1}{2}=e^\frac{-2}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{2})=\frac{-2}{\frac{L}{R}}$

⇒ $log(2)=\frac{2}{\frac{L}{R}}$

⇒ $\frac{L}{R}=\frac{2}{log2}$

Now substitute $i(t)=\frac{3}{4}imax=\frac{3E}{4R}$

⇒ $\frac{3E}{4R}=\frac{E}{R}(1-e^\frac{-t}{\frac{L}{R}})$

⇒ $\frac{3}{4}=1-e^\frac{-t}{\frac{L}{R}}$

⇒ $\frac{1}{4}=e^\frac{-t}{\frac{L}{R}}$

Applying logarithm on both sides,

⇒ $log(\frac{1}{4})=\frac{-t}{\frac{L}{R}}$

⇒ $log(4)=\frac{t}{\frac{L}{R}}$

⇒ $t=log4\frac{L}{R}$

now subs. $\frac{L}{R}=\frac{2}{log2}$

⇒ $t=log4\frac{2}{log2}$

also $log4=log2^{2}=2log2$

⇒ $t=2log2\frac{2}{log2}$

⇒ $t=4$

5 0

2 years ago

What is the kinetic energy of a 9.0 kg steelhead if its speed is 16 m/s?

Vesnalui [34]

We are given:

Mass of the Steelhead(m) = 9 kg

Velocity of the Steelhead(v) = 16 m/s

Calculating the Kinetic Energy:

KE = 1/2mv²

replacing the variables

KE = 1/2 * 9 * (16)²

KE = 1152 Joules

8 0

2 years ago

If blue light hits a red filter, what kind of light comes through the filter?

kotegsom [21]

It can be either C or B

Reasons it can be C: Red and Blue together(if I'm correct in art) is the combined color of two of the 3 primary colors to get a purple/violet color and if said filter is see through or just too dense for the light to even penetrate the said filter(in theory) but all in all purple is the answer with the two primary colors blue and red.

But also, it depends on what kind of filter it is, if the filter is like a screen filter then it will just come out in blue with the slightly different colors of again purple but in a darker tone then the actual eye can see.

Or it can be just C again cause the filter can be a film but that's a bit too far and to complex for right now so I believe it is B

8 0

3 years ago

What two forces are balanced in what we call gravitational equilibrium? What two forces are balanced in what we call gravitation

JulijaS [17]

Question:

What two forces are balanced in what we call gravitational equilibrium?

A) the electromagnetic force and gravity

B) outward pressure and the strong force

C) outward pressure and inward gravity

D) the strong force and gravity

E) the strong force and kinetic energy

Answer:

The correct answer is C) Outward Pressure and Inward gravity

Explanation:

Gravitational equilibrium is a balance between the inward pull of gravity and the outward push of internal gas pressure. It also refers to the condition of a star in which the weight of overlying layers at each point is balanced by the total pressure at that point.

As the weight increases in the lower layers of the sun, the pressure also increases to maintain this balance. So you find that the outward push of pressure balances the inward pull of gravity thus creating an equilibrium.

Why is gravitational equilibrium important?

The simple answer is balance. If for instance the sun as a stable star (which has gravitational equilibrium) loses it's balance, it becomes highly unstable and prone to violent outbursts. These outbursts are caused by the very high radiation pressure at the star's upper layers, which blows significant portions of the matter at the "surface" into space during eruptions that may rage for several years. Of course such a condition is adverse to the existence and support of life.

Cheers!

6 0

3 years ago

An emission ray has a frequency of 5.10 × 10¹Ê Hz. Given that the speed of light is 2.998 × 10§ m/s, what is the wavelength of t

scoundrel [369]

The answer is 5.88 · 10⁻⁷ m.

To calculate this we will use the light equation:

v = λ · f,
where:
v - the speed of light (units: m/s)
λ - the wavelength of the ray (units: m)
f - the frequency of the ray (units: Hz = 1/s since Hz means cycles per second (f=1/T))

It is given:
f = 5.10 · 10¹⁴ Hz = 5.10 · 10¹⁴ 1/s
v = 2.998 · 10⁸ m/s
λ = ?

If v = λ · f, then λ = v ÷ f:
λ = 2.998 · 10⁸ m/s ÷ 5.10 · 10¹⁴ 1/s
= 0.588 · 10⁸⁻¹⁴ · m
= 0.588 · 10⁻⁶ m
= 5.88 · 10⁻⁷ m

6 0

3 years ago