WHOEVER ANSWERS FIRST WILL BE MARKED BRAINLIEST!

You are working at a company that manufactures electrical wire. Gold is the most ductile of all metals: it can be stretched into

devlian [24]

Answer: $R=1.424 M\Omega$

Explanation:

Given

mass of gold $m=1.6 gm$

Length of wire $L=2.2 km$

Resistivity of gold $\rho =2.44\times 10^{-8}$

density of gold $=19.3\times 10^3 kg/m^3$

and $mass=volume\times density$

$1.6\times 10^{-3}=volume\times 19.3\times 10^3$

$volume=8.29\times 10^{-8} m^3$

And $Resistance R=\frac{\rho L}{A}$

also be written as

$R=\frac{\rho L^2}{V}$

where $L=length$

$V=volume$

$\rho =resistivity\ of\ gold$

$R=\frac{2.44\times 10^{-8}\times (2200)^2}{8.29 \times 10^{-8}}$

$R=1.42\times 10^{6} \Omega$

$R=1.424 M\Omega$

5 0

3 years ago

A 3-kg ball is thrown with a speed of 8 m/s at an unknown angle above the horizontal. The ball attains a maximum height of 2.8 m

Alina [70]

Answer:

13.5 J

Explanation:

mass of ball, m = 3 kg

maximum height, h = 2.8 m

initial speed, u = 8 m/ s

Angle of projection, θ

use the formula of maximum height

$H = \frac{u^{2}Sin^{2}\theta }{2g}$

$2.8 = \frac{8^{2}Sin^{2}\theta }{2\times 9.8}$

Sin θ = 0.926

θ = 67.8°

The velocity at maximum height is u Cosθ = 8 Cos 67.8 = 3 m/s

So, kinetic energy at maximum height

$K=\frac{1}{2}mv^{2}$

K = 0.5 x 3 x 3 x 3

K = 13.5 J

8 0

4 years ago

An electromagnetic wave is transporting energy in the negative y direction. At one point and one instant the magnetic field is i

natali 33 [55]

Answer:. Option c

Explanation: the speed of an electromagnetic wave is simply the vector product of the magnetic field and the electric field.

The direction of the velocity is the direction of the electromagnetic wave.

The wave is already moving towards the negative y axis (-j) and the magnetic field is already pointing towards the positive x axis (i)

From cross product of unit vectors

i × j = k

i × k = - j

With the second identity, we can see that the electric field will be pointing towards the positive of the x axis (k).

Option c is validated

4 0

3 years ago

Which scientist was the first to use the telescope in astronomy

Mashutka [201]

Answer:

Galileo Galilei

Explanation:

although Galileo was not the scientist who invented the telescope, he was the first to use it to observe celestial objects. he used the telescope in 1609. his discovery included more accurate information about the moon, the sun and some of the planets.

4 0

4 years ago

A student drops an object out the window of the top floor of a high-rise dormitory.

seropon [69]

-- The acceleration due to gravity is 32.2 ft/sec² . That means that the
speed of a falling object increases by an additional 32.2 ft/sec every second.

-- If dropped from "rest" (zero initial speed), then after falling for 4 seconds,
the object's speed is (4.0) x (32.2) = 128.8 ft/sec.

-- 128.8 ft/sec = 87.8 miles per hour

Now we can switch over to the metric system, where the acceleration
due to gravity is typically rounded to 9.8 meters/sec² .

-- Distance = (1/2) x (acceleration) x (time)²

D = (1/2) (9.8) x (4)² = 78.4 meters

-- At 32 floors per 100 meters, 78.4 meters = dropped from the 25th floor.

The 5 points are certainly appreciated, but I do wish they were Celsius points.

3 0

3 years ago