All categories

3 years ago

The spread of fire from the ground floor to an upper floor of a building primarily due to heat transfer by

1 answer:

4 0

The correct answer is by convection.

In fact, in a fluid (like the air in the room full of fire) the warmer parts of the fluid move upward, replacing the colder parts which go down. For this very same reason, the fire spreads moving toward the upper floors of the bulding.

You might be interested in

When the comet passes close to the sun, it has a visible tail. Typically, the comet is only visible for a matter of days while i

Nataly [62]

Answer:

The comet is locked in the Sun's gravity. as it falls deeper in the gravity we'll, its velocity increases. As is travels closer to the Sun, it is trying to break away, but cannot. This transforms into a sideways movement that produces a tight turn. It races further out of the gravity well, and sheds velocity.

7 0

3 years ago

1) Consider an electric power transmission line that carries a constant electric current of i = 500 A. The cylindrical copper ca

JulsSmile [24]

Answer:

t = 1.27 x 10⁹ s

Explanation:

First, we will find the volume of the wire:

Volume = V = AL

where,

A = Cross-sectional area of wire = πr² = π(1 cm)² = π(0.01 m)² = 3.14 x 10⁻⁴ m²

L = Length of wire = 150 km = 150000 m

Therefore,

V = 47.12 m³

Now, we will find the number of electrons in the wire:

No. of electrons = n = (Electrons per unit Volume)(V)

n = (8.43 x 10²⁸ electrons/m³)(47.12 m³)

n = 3.97 x 10³⁰ electrons

Now, we will use the formula of current to find out the time taken by each electron to cross the wire:

$I =\frac{q}{t}$

where,

t = time = ?

I = current = 500 A

q = total charge = (n)(chareg on one electron)

q = (3.97 x 10³⁰ electrons)(1.6 x 10⁻¹⁹ C/electron)

q = 6.36 x 10¹¹ C

$500\ A = \frac{6.36\ x\ 10^{11}\ C}{t}\\\\t = \frac{6.36\ x\ 10^{11}\ C}{500\ A}$

Therefore,

7 0

3 years ago

A 326 g object is attached to a spring and executes simple harmonic motion with a period of 0.250 s. If the total energy of the

Basile [38]

Answer:

a) $v_{max}=5.98\frac{m}{s}$

b) $k=205.92\frac{N}{m}$

c) $A=0.24m$

Explanation:

a) In the equilibrium position of the system, that is when the spring is not elongated, the potential energy is zero. Therefore, the total energy of the system is the maximum kinetic energy:

$E=K_{max}\\E=\frac{mv_{max}^2}{2}\\v_{max}=\sqrt{\frac{2E}{m}}\\v_{max}=\sqrt{\frac{2(5.83J)}{0.326kg}}\\v_{max}=5.98\frac{m}{s}$

b) The force constant of the spring can be calculated from the natural frequency of the system:

$\omega^2=\frac{k}{m}\\k=m\omega^2$

Recall that $\omega=\frac{2\pi}{T}\\$ , that is the distance traveled in one revolution divided into the time of one revolution. Replacing and solving for k:

$k=\frac{m4\pi^2}{T^2}\\k=\frac{(0.326kg)4\pi^2}{(0.25s)^2}\\k=205.92\frac{N}{m}$

c) The maximum speed is directly proportional to the amplitude of the motion:

$v_{max}=A\omega\\A=\frac{v_{max}}{\omega}\\A=\frac{(v_{max})T}{2\pi}\\A=\frac{(5.98\frac{m}{s})0.25s}{2\pi}\\A=0.24m$

3 0

3 years ago

Write a paragraph that explains how one gene can be responsible for many traits, and how how many genes can be responsible for o

gayaneshka [121]

A gene is made of up several DNA's and these DNA's can be be responsible for many traits. There are also DNA's that contain the information on how the cells works and not on the traits of an organism. Therefore, one gene can have several DNA's that contain information about traits and another gene can have only a single DNA that contains information about a trait.

5 0

3 years ago

Which other type of electromagnetic wave will strip away electrons from the zinc plate? And why?

garik1379 [7]

In short, when light illuminates a piece of metal, the light kicks off electrons from the metal’s surface and these electrons can be detected as a change in the electric charge of the metal or as an electric current. Hence the name: photo for light and electric for the current. The explanation behind this simple phenomenon opened the door to revolutionary modern physics concepts regarding the composition of light, quantum mechanics, and what is now referred to as the “wave-particle duality” of nature. The wave-particle duality of nature is perhaps one of the greatest mysteries of our universe and a very interesting philosophical subject! Your goal in this lab is to reproduce the photoelectric effect for yourselves and to understand how it demonstrates the particle behavior of light.

8 0

3 years ago

Read 2 more answers