Two examples of chemical reactions that involved a thermal energy change:
1. NH4NO3 (s) + heat ---> NH4+ (aq) + NO3 (aq)
2. CaCl2 (s) + 2H20 ---> Ca(OH)2 (aq) + 2HCl (g) + heat
Which is exothermic? Which is endothermic? How do you know?

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:

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:

it is maybe A but i'm not 100% sure

Explanation:

its the only one that is mixed

Answer:

6.86 N

Explanation:

Applying,

F = mg............... Equation 1

Where F = Force exerted by gravity on the mass, m = mass, g = acceleration due to gravity

Note: The Force exerted by gravity on the mass is thesame as the weight of the body.

From the question,

Given: m = 700 g = (700/1000) = 0.7 kg

Constant: g = 9.8 m/s²

Substitute these values into equation 1

F = 9.8(0.7)

F = 6.86 N

Answer: A.0,0097s

Mas a unidade aí deveria ser Hertz (Hz)

Explanation:

Answer:

103 hz

Explanation:

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:

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

Answer:

I think C

Explanation:

If im right give brainliest :)

c- temperature

The speed of sound increases with increasing temperature .

Answer:

hi i only dont understand want ur saying

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:

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

Answer:

undergone a chemical change

Explanation:

Answer:

undergone a chemical change

Explanation:

An oven thermostat regulates the temperature inside an oven. The thermostat's temperature-sensitive probe measures the oven's warmth, switching the heat on and off as necessary to maintain the correct temperature.

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:

44.1 m

Explanation:

Consider the displacement being x:

x = (g•t²)/2

x = (9.8•3²)/2

x = (9.8•9)/2

x = 88.2/2

x = 44.1 m

Answer:

Explanation:

that's the correct answer

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:

momentum (d) it's s preety easy haaaaaaaa

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

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.

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

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:

A

Explanation:

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

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:

B

A

Explanation:

please mark as brainliest :)

Answer:

Water can spread germs through bacteria.

Explanation:

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

Answer:

HOPE IT HEPLED U !!!!

Explanation:

i think it's (C) They have different units ....

Answer:

Nitric acid, also known as aqua fortis and spirit of niter, is a highly corrosive mineral acid. The pure compound is colorless, but older samples tend to acquire a yellow cast due to decomposition into oxides of nitrogen and water. Most commercially available nitric acid has a concentration of 68% in water.

Explanation:

Good morning...

Nitric acid production is mainly driven by fertilizer industry. Nitric acid is used in the production of ammonium nitrate and calcium ammonium nitrate which find applications as fertilizers.

Answer:

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

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