need help with this!

just scienceeeeeee

Answer:

B

A

Explanation:

please mark as brainliest :)

Complete question:

(b) How much energy must be supplied to boil 2kg of water? providing that the specific latent heat of vaporization of water is 330 kJ/kg. The initial temperature of the water is 20 ⁰C

Answer:

The energy that must be supplied to boil the given mass of the water is 672,000 J

Explanation:

Given;

mass of water, m = 2 kg

heat of vaporization of water, L =  330 kJ/kg

initial temperature of water, t = 20 ⁰C

specific heat capacity of water, c = 4200 J/kg⁰C

Assuming no mass of the water is lost through vaporization, the energy needed to boil the given water is calculated as;

Q = mc(100 - 20)

Q = 2 x 4200 x (80)  

Q = 672,000 J

Q = 672,000 J

Q = 672,000 J

Therefore, the energy that must be supplied to boil the given mass of the water is 672,000 J

Answer:

Pressure = 39200 N/m²

Explanation:

Given the following data;

Mass = 60 kg

Area = 150 cm²

Conversion:

1 centimeter square = 0.0001 meter square

150 centimeter square = 150 * 0.0001 = 0.015 m²

To find the pressure exerted on the ground by the person;

Mathematically, pressure is given by the formula;

[tex] Pressure = \frac {Force}{area} [/tex]

First of all, we would determine the force exerted by the person.

Force = mass * acceleration due to gravity.

We know that acceleration due to gravity is equal to 9.8 m/s².

Substituting into the formula, we have;

Force = 60 * 9.8

Force = 588 Newton

Next, find the pressure;

[tex] Pressure = \frac {Force}{area} [/tex]

Substituting into the formula, we have;

[tex] Pressure = \frac {588}{0.015} [/tex]

Pressure = 39200 N/m²

Answer:

I think C

Explanation:

If im right give brainliest :)

Answer:

R = 4.77 ohms

Explanation:

Four resistors are given such that,

R₁ = 2 ohms

R₂ = 3 ohms

R₃ = 5 ohms

R₄ = 10 ohms

Here, R₁ and R₂ in series. The equivalent is given by :

R₁₂ = R₁ + R₂

= 2 + 5

R₁₂ = 7 ohms

Similarly, R₃ and R₄ are in series. so,

R₃₄ = R₃ + R₄

= 10+5

R₃₄ = 15 ohms

Now, R₁₂ and R₃₄ are in parallel. So,

[tex]\dfrac{1}{R}=\dfrac{1}{R_{12}}+\dfrac{1}{R_{34}}\\\\\dfrac{1}{R}=\dfrac{1}{7}+\dfrac{1}{15}\\\\R=4.77\ \Omega[/tex]

So, the equivalent resistance s 4.77 ohms.

Answer:

The solution is neither acidic or basic,

PH < 7    acidic

PH = 7    neutral

PH > 7 basic

It is a measure of the (H+) hydronium concentration.

Answer:

B. When the independent variable composed of categories and does not show a relationship to the dependent variable

Explanation:

A bar graph, is a graph used for presenting data grouped into categories, which are the independent variables of the graph, and the measurement of each category, which are represented as rectangular bars having lengths proportional to the value of the category, on a chart

In the bar graph or chart, there is no direct relationship between the categories, which are the x-values and the dependent variables , which are the length of the bars, the y-values, as the length of the rectangular bar in one category, cannot be obtained from another category through a relationship

Therefore, the correct option is option is when the independent variable composed of categories and does not show a relationship to the dependent variable

Answer:

Las estrellas se forman debido a la unión de pequeños elementos y partículas como el hidrógeno y el helio que experimentan una fusión nuclear en el núcleo debido a la intensa presión para formar un nuevo átomo (como dos hidrógeno que se combinan para formar un átomo de helio) que es un proceso. que requiere una gran cantidad de energía para comenzar, por lo que cada reacción de fusión produce una gran cantidad de energía que puede mantener la reacción y equilibra la fuerza gravitacional que atrae las masas de las partículas hacia el centro de la estrella

A medida que la energía de la estrella se irradia, la superficie de la estrella cede la energía en forma de calor y luz de manera que debido a la alta temperatura de las partículas de los átomos de los elementos se mueven muy rápida y energéticamente para emitir fotones rápidamente. (alta frecuencia) que se ve como el alto brillo de la estrella

Explanation:

Answer:a gas at pressure of 0.8 m column of H g

Answer:

v = 3.53x10⁻³ m/s.

Explanation:

We can find the velocity of the rock by energy conservation:

[tex] \Sigma E_{i} = \Sigma E_{f} [/tex]        

[tex] \frac{1}{2}kx^{2} = \frac{1}{2}mv^{2} [/tex]

Where:

i is for initial and f is for final

k: is the stiffness of the rubber = 20 N/m

x: is the distance of the rubber compression = 5 mm = 0.005 m

m: is the mass of the stone = 40 kg

v: is the velocity =?

Hence, the velocity is:

[tex]v = \sqrt{\frac{kx^{2}}{m}} = \sqrt{\frac{20 N/m(0.005 m)^{2}}{40 kg}} = 3.53 \cdot 10^{-3} m/s[/tex]

Therefore, the velocity with which the stone leaves the catapult is 3.53x10⁻³ m/s.

I hope it helps you!  

Answer:

40000 N/m²

Explanation:

Applying,

P =  F/A................... Equation 1

Where P = Pressure, F = Force, A = Area.

From the question,

The force(F) exerted by the person's foot is thesame as it's weight.

F = W = mg............ Equation 2

Where m = mass of the person, g = acceleration due to gravity.

Substitute equation 2 into equation 1

P = mg/A................ Equation 3

Given: m = 60 kg, g = 10 m/s², A = 150 cm² = (150/10000) m² = 0.015 m²

Substitute these values into equation 3

P = (60×10)/0.015

P = 600/0.015

P = 40000 N/m²

Answer:

B line graph

Explanation:

sorry if I am wrong

Answer:

b

Explanation:

Answer:

pretty sure its studying the atomic structure of a solid carbon dioxide. so c

Explanation:

Answer:

B. Studying the atomic structure of solid carbon dioxide

Explanation:

This is known as crystallography, the study of the arrangement of atoms in a solid, and it is a popular branch of solid-state physics.

Hope this helps :)

Answer:

my brainly answer got deleted for no reason but its velocity thats the name of speed in 1 direction

Explanation:

Answer:

Hello There!!

Explanation:

1/2R because wire B has twice the radius,it has four times the cross-sectional area of wire A.

hope this helps,have a great day!!

~Pinky~

Answer:

the power output P = 1484 W

Explanation:

Power P  = Force× speed

Given that motor of a battery-powered scooter can maintain a speed of 5.3 m/s by providing a force of 280 N.

Therefore,the power output of the motor P = 280×5.3 = 1484 W

Hence, the power output P = 1484 W

Option C: Later in the day, less power is developed in lifting each box

Answer:

Later in the day, less power is developed in lifting each box.

power= workdone÷time

Answer:

i. 2.5 kHz ii. 5 kHz

Explanation:

The frequency of the wave in the rod is given by f = nv/2L where n = harmonic, v = speed of sound in rod = 5000 m/s and L = length of rod = 1 m

i. f1

For f1, n = 1

f1 = 1 × v/2L

= v/2L

Substituting the values of the variables into the equation, we have

= 5000 m/s ÷ (2 × 1 m)

= 5000 m/s ÷ 2 m

= 2500 /s

= 2500 Hz

= 2.5 kHz

ii. f2

For f2, n = 2

f2 = 2 × v/2L

= v/L

Substituting the values of the variables into the equation, we have

= 5000 m/s ÷ 1 m  

= 5000 /s

= 5000 Hz

= 5 kHz

Answer:

.04 kg m/s

Explanation:

Momentum is simply mass multiplied by velocity given by p = mv. You can consider momentum as mass in motion.

Before the collision, the data given for the toy train:

v = 0.5m/s

m = 75g

We need to convert grams into the SI unit of mass, kg.

75g / 1000g * 1kg = 0.075kg

Using p = mv, we can determine:

p = 0.075kg * 0.5m/s = 0.0375 kg m/s

Rounding to the value of 1 sig-fig, it comes out to be 0.04 kg m/s.

Answer:

m=6.25kg

Explanation:

Force= mass × acceleration

50=m×8

make m subject of the formula...

m=50/8

m=6.25kg

Answer:

[tex]\boxed {\boxed {\sf 6.25 \ kilograms}}[/tex]

Explanation:

According to Newton's Second Law of Motion, force is the product of mass and acceleration.

[tex]F= m \times a[/tex]

We know the force is 50 Newtons and the acceleration is 8 meters per second squared. Let's convert the units to make the problem and unit cancellation easier.

1 Newton is equal to 1 kilogram meter per square second (1 kg*m/s²), so the force of 50 N is equal to 50 kg*m/s².

Now we know 2 values:

Substitute the values into the formula.

[tex]50 \ kg *m/s^2= m \times 8 \ m/s^2[/tex]

Since we are solving for the mass, we must isolate the variable, m. It is being multiplied by 8 meters per square second and the inverse of multiplication is division. Divide both sides by 8 m/s².

[tex]\frac {50 \ kg *m/s^2}{8 \ m/s^2}= \frac{m \times 8 \ m/s^2}{8 \ m/s^2}[/tex]

[tex]\frac {50 \ kg *m/s^2}{8 \ m/s^2}= m[/tex]

The units of meters per square second (m/s²) cancel.

[tex]\frac {50 \ kg }{8 }=m[/tex]

[tex]6.25 \ kg =m[/tex]

The mass is 6.25 kilograms.

Answer:

451.13 J/kg.°C

Explanation:

Applying,

Q = cm(t₂-t₁)............... Equation 1

Where Q = Heat, c = specific heat capacity of iron, m = mass of iron, t₂= Final temperature, t₁ = initial temperature.

Make c the subject of the equation

c = Q/m(t₂-t₁).............. Equation 2

From the question,

Given: Q = 1500 J, m = 133 g = 0.113 kg, t₁ = 20 °C, t₂ = 45 °C

Substitute these values into equation 2

c = 1500/[0.133(45-20)]

c = 1500/(0.133×25)

c = 1500/3.325

c = 451.13 J/kg.°C

Answer:While walking, one foot is in contact with the ground at a time. The surface area of one foot is less than two feet. Therefore, the pressure is more than the pressure exerted while standing, as the surface area of both feet is more.

Answer:

undergone a chemical change

Explanation:

Answer:

undergone a chemical change

Answer:

Water can spread germs through bacteria.

Explanation:

Bacteria can live in water and can spread to new locations when water is moved.

Answer: A.0,0097s

Mas a unidade aí deveria ser Hertz (Hz)

Explanation:

Answer:

103 hz

Explanation:

Answer:

A

Explanation:

because she wants to practice science and A is the practical option.

The average velocity is 25 mph north.

Average velocity = displacement/time

Displacement =

(400 mi north) + (275 mi south)

Displacement = 125 mi north

Average V = (125 mi north) / 5 hours.

Average V = 25 mph north

For 1000 seconds , a current of 0.1 A flows so as to transfer charge of 100C

Answer:

Which of the following... : constant velocity horizontal motion

A ball is thrown at certain... : 0 m/s