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3 years ago

you have one 100 ohm resistor what size resistor must you hook up in parallel in order to have a resistance of 99.0

Physics

1 answer:

romanna [79]3 years ago

7 0

Answer:

The resistor to be hooked up must be 9900 $\Omega$

Explanation:

Recall how resistors in parallel combine to render an equivalent resistor:

$\frac{1}{R_e} =\frac{1}{R_1} +\frac{1}{R_2}$

So we need to find which resistor (R2) we need to combine in parallel with resistor R1 (100 $\Omega$ ) in order to obtain an equivalent resistor Re (99 $\Omega$ ) :

$\frac{1}{99} =\frac{1}{100} +\frac{1}{R_2}\\\frac{9900\,R_2}{99} =\frac{9900\,R_2}{100} +\frac{9900\,R_2}{R_2}\\100\,R_2= 99\,R_2+9900\\R_2=9900\,\,\Omega$

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Ms. Paul is standing at the top of a cliff that is 100 m tall. She kicks a rock and it gets a horizontal velocity of 15.0 m/s. D

Lynna [10]

vertical motion

h=1/2 gt²

100 = 1/2 x 10 x t²

t² = 100/5 = 20

t = 2√5 s

horizontal motion

x = v.t

x = 15 x 2√5

x = 30√5 m

3 0

2 years ago

Light takes 8 minutes to reach the Earth, and the speed of light is 3.0×10^8 m/s. a) What is the orbital speed of the Earth arou

spin [16.1K]

Answer:

(a) 28690 m/s (b) $2.46x10^{33}J$

Explanation:

The orbital speed is define as:

$v = \frac{2 \pi r}{T}$ (1)

Where r is the radius of the trajectory and T is the orbital period.

To determine the orbital speed of the Earth it is necessary to know the orbital period and the radius of the trajectory. That can be done by means of the Kepler's third law and average velocity equation.

The average velocity in a Uniform Rectilinear Motion is defined as:

$v = \frac{d}{t}$ (2)

Where v is the velocity, d is the covered distance and t is the time.

Equation 2 can be rewritten for d to get:

$d = vt$ (3)

In this case, v will be the speed of light and t, the 8 minutes that takes to reach the Earth.

The time will be converted to seconds so the units in equation 3 can match:

$8min . \frac{60s}{1min}$ ⇒ $480s$

$t = 480s$

Replacing all those values in equation 3 it is gotten:

$d = (3.0x10^{8}m/s)(480s)$

$d = 1.44x10^{11}m$

Kepler’s third law is defined as:

$T^{2} = r^{3}$

Where T is orbital period and r is the radius of the trajectory.

$T = \sqrt{r^{3}}$

$T = \sqrt{(1.44x10^{11}m)^{3}}$

It is necessary to pass from meters to astronomical unit (AU), 1 AU is defined as the distance between the Earth and the Sun.

$T = \sqrt{1AU}$

$T = 1AU$

That can be expressed in units of years.

$T = 1AU . \frac{1year}{1AU}$

$T = 1year$

But there are 31536000 seconds in one year:

$T = 1year . \frac{31536000s}{1year}$

$T = 31536000s$

Finally, equation 1 can be used:

$v = \frac{2 \pi (1.44x10^{11}m)}{(31536000s)}$

$v = 28690 m/s$

So Earth orbital speed around the Sun is 28690 m/s.

b) What is its kinetic energy?

The kinetic energy is defined as:

$E = \frac{1}{2}mv^{2}$ (4)

Notice that it is necessary to found the mass of the Earth, that can be done combining the Universal law of gravity and Newton's second law:

$F = \frac{GMm}{r^{2}}$

$ma = \frac{GMm}{r^{2}}$ (5)

M will be isolated in equation 5:

$M = \frac{r^{2}a}{G}$

Where r is the radius of the Earth ( $6.38x10^{6}m$ )

$M = \frac{(6.38x10^{6}m)^{2}(9.8m/s^{2})}{6.67x10^{-11}kg.m/s^{2}.m^{2}/Kg^{2}})$

$M = 5.98x10^{24} Kg$

$E = \frac{1}{2}( 5.98x10^{24} Kg))(28.690m/s)^{2}$

$E = 2.46x10^{33}Kg.m^{2}/s^{2}$

$E = 2.46x10^{33}J$

Hence, the kinetic energy of Earth is $2.46x10^{33}J$ .

8 0

3 years ago

WILL GIVE BRAINLEST!!

polet [3.4K]

I think the answer is c

7 0

4 years ago

Analyze that, “Convection is equal to the Conduction plus fluid flow.”

igomit [66]

Answer:

Convection is equal to the conduction plus fluid flow.

Explanation:

Convection is a mode of heat transfer that requires the movement of the molecules of the medium from one point to another. It takes place majorly in fluids (liquids and gases). While conduction is a process by which heat is transfered by the vibtation of molecules of a medium at their possitions, thereby colliding with other neighbouring molecules to transmit heat.

Before convection could occur, there must be conduction of heat by the molecules of the medium which causes their motion. According to the kinetic molecular theory, any molecule of the medium close to the source of heat conducts heat, becomes less dense and thus moves so that its initial position would be occupied by another denser molecule. This continous process generate convection or convectional current. Therefore, convection is as a result of conduction and fluid flow because a molecule must first conduct heat before it moves.

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3 years ago

“Do you think that the role of culture, gender,

Serjik [45]

Answer:

this is based on your opinion but mine is...

Explanation:

Do you think that the role of culture, gender, and/or race has changed in sclence between the times we are learning about and today's times? If so, how? If not, explain your thoughts?

Yes by how because Race’ cannot be biologically defined due to genetic variation among human individuals and populations. (A) The old concept of the “five races:” African, Asian, European, Native American, and Oceanian. According to this view, variation between the races is large, and thus, the each race is a separate category. Additionally, individual races are thought to have a relatively uniform genetic identity. (B) Actual genetic variation in humans. Human populations do roughly cluster into geographical regions. However, variation between different regions is small, thus blurring the lines between populations. Furthermore, variation within a single region is large, and there is no uniform identity.

3 0

3 years ago