A car travels between 100-mile and 25-mile markets on a highway in 3 hours. The average speed of the car during the interval is

5. Define joint<br><br> answer asap plz and ty

Inessa [10]

A point at which parts of an artificial structure are joined. Hope this helps

4 0

3 years ago

A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed

mafiozo [28]

Answer:

0.6375 m/s

Explanation:

Let x be the distance of the man from the building

from the figure attached

initially the value of x=12

Given:

$\frac{dx}{dt}=-1.7m/s$

where the negative sign depicts that the distance of the man from the building is decreasing.

Now, Let The length of the shadow be = y

we have to calculate $\frac{dy}{dt}$ when x=4

from the similar triangles

we have,

$\frac{2}{12-x}=\frac{y}{12}$

or

$y=\frac{24}{12-x}$

Differentiating with respect to time 't' we get

$\frac{dy}{dt}=-\frac{24}{12-x}^2\frac{-dx}{dt}$

or

$\frac{dy}{dt}=\frac{24}{12-x}^2\frac{dx}{dt}$

Now for x = 4, and $\frac{dx}{dt}=-1.7m/s$ we have,

$\frac{dy}{dt}=\frac{24}{12-4}^2\times (-1.7)$

or

$\frac{dy}{dt}=-0.6375m/s$

<u>here, the negative sign depicts the decrease in length and in the question it is asked the decreasing rate thus, the answer is </u><u>0.6375m/s</u>

4 0

3 years ago

A parallel-plate vacuum capacitor has 8.38 J of energy stored in it. The separation between the plates is 2.30 mm. If the separa

Elanso [62]

Answer:

Explanation:

plate separation = 2.3 x 10⁻³ m

capacity C₁ = ε A / d

= ε A / 2.3 x 10⁻³

C₂ = ε A / 1.15 x 10⁻³

$\frac{C_2}{C_1}$ = $\frac{2.3}{1.15}$

a ) when charge remains constant

energy = $\frac{q^2}{2C}$

q is charge and C is capacity

energy stored initially E₁= $\frac{q^2}{2C_1}$

energy stored finally E₂ = $\frac{q^2}{2C_2}$

$\frac{E_1}{E_2} = \frac{C_2}{C_1}$ = $\frac{2.3}{1.15}$

$E_2$ = $\frac{1.15}{2.3 } \times E_1$

= $\frac{1.15}{2.3 } \times 8.38$

= 4.19 J

b )

In this case potential diff remains constant

energy of capacitor = 1/2 C V²

energy is proportional to capacity as V is constant .

$\frac{E_2}{E_1} = \frac{C_2}{C_1}$

$\frac{E_2}{8.38} = \frac{2.3}{1.15}$

$E_2$ = 16.76 .

8 0

3 years ago

What can be inferred when an atom is electrically charged?

Elena-2011 [213]

When an atom becomes electrically charged the number of electrons or protons stops and they are not equal again. The "extra" electron or proton is not balanced by something inside the atom any longer and it starts attracting itself to othet protons or electrons in other atoms.

<h3>What is atomic structure?</h3>

An atomic structure comprises of positively charged nucleus which is surrounded by negatively charged particles called electron and neutron which is neutral charged.

Unlike charges attract each other while like charges repel each other.

Therefore, When an electron is fully charged, the number of electrons will stop to be unequal again.

Learn more about Atomic charge here.

brainly.com/question/18102056

7 0

2 years ago

Humans obtain energy in a number of different ways. About half of the electrical energy in the U.S. is generated by burning coal

ivanzaharov [21]

Answer:

C. Burning coal tends to harm the environment more than using solar panels.

Explanation:

When coal is burned, it reacts with the oxygen in the air. This reaction converts the stored potential energy, which turns into thermal energy, which is released as heat. But it also produces methane and carbon dioxide which is released into the air.

6 0

3 years ago