physics class 9 chapter 8 please tell​ please

Answer: frequency 137.5

Time period 0.01sec

Explanation:

Answer:

C: the process by which stars create the heavier elements

Explanation:

Stellar nucleosynthesis is defined as the process of nuclear fusion by which heavier elements are formed within stars by from the combination of protons and neutrons gotten from the nuclei of lighter elements.

Looking at the options, the correct one is Option C

Answer:

The field is parallel to the direction of flow of the current.

Answer:

750 N

Explanation:

the tension on the rope is the weight of the hero

Answer:

Explanation:

What we are basically looking for here is how long it takes the first stone to hit the water. We have everything we need to figure that out. We will use the equation

Δx = . Filling in, we will solve for t, the time is takes the first stone to hit the water (which is the same for both since they both hit the water at the same time):

which is a quadratic that we will have to factor. Get it into standard form, setting it equal to 0:

and factor to get that

t = 3.2 s and t = -2.8 s

Since time can't ever be negative, it takes 3.2 s for the stones to hit the water.

Answer:

Jo

Explanation:

irradiating food doesn't make it radioactive (that's contamination) and beta particles are stopped by aluminium foil or thin metals, so it may not pass through thick packaging (usually gamma is used to irradiate foods as it can pass through the packaging)

Answer:

Burning paper

Explanation:

The tarnishing of iron is a chemical process, and the only option that is a chemical process is Burning paper

Answer:

F2 = 900 lbs

Explanation:

From pascal principle;

F1/A1 = F2/A2

Force on cylinder at left; F1 = 100 lbs

Diameter of cylinder at left; d1 = 2 inches

Diameter of cylinder at right; d2 = 6 inches

Formula for area of top of cylinder = πr²

Thus;

Area of top of left cylinder; A = π × 2² = 4π

Area of top of right cylinder; A = π × 6² = 36π

Thus;

100/4π = F2/36π

F2 = (36π × 100)/4π

F2 = 900 lbs

Answer:

True

Explanation:

True, atoms create electromagnetic fields that form repulsion to keep them from touching.

Answer:

Carryonlearning

Answer:

25 km/hr

Explanation:

Since Ali's average speed for his trip to school is u = 20 km/hr and his average speed for the return trip to back home from school is v = 30 km/hr, thus his total average speed for the journey is thus V = (initial average speed + final average speed)/2 = (u + v)/2

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

V = (u + v)/2

V = (20  km/hr + 30 km/hr)/2

V = 50 km/hr/2

V = 25 km/hr

So, the average speed for Ali's trip is 25 km/hr

Answer:

Deflating the tires by pulling the valve stems

Explanation:

When an accident happens, the EMT process is to take off the top of the vehicle of the highly damaged vehicle so that it can easily be assessed to rescue the vehicle occupants. This creates a bigger exit for the rescuers to take out the people. Vehicle extrication means removing the vehicle from around someone involved in a fatal collision, when other other ways of exiting is not advised or possible. to stabilize the vehicle you have to deflate all tires by pulling the valve stems.

Answer:

MKS stands for Meter, Kilogram and second. In this system of unit mass is given in Kilogram, length in meter and time in second. ... CGS system stands for Centimeter- Gram- Second system. In CGS system, length is measured in centimeters mass is measured in grams and time is in seconds.

Answer:

The correct option is a) 10 mph, 0 mph.

Explanation:

1. The average speed (S) is a magnitude given by:

[tex] S = \frac{D}{T} [/tex]  

Where:

D: is the total distance = 1 mi

T: is the total time = 6 min

[tex] S = \frac{D}{T} = \frac{1 mi}{6 min}*\frac{60 min}{1 h} = 10 mph [/tex]

Hence, the average speed is 10 mph.

2. The average velocity is a vector:

[tex] V = \frac{\Delta d}{\Delta t} = \frac{d_{f} - d_{i}}{t_{f} - t_{i}} [/tex]

Where:

[tex]d_{f}[/tex]: is the final distance                                    

[tex]d_{i}[/tex]: is the initial distance  

[tex]t_{f}[/tex]: is the final time                

[tex]t_{i}[/tex]: is the initial time

Since Juanita ran one mile around her school track, the final position is the same that the initial position, so the magnitude of the average velocity is zero.                                               

Therefore, the correct option is a) 10 mph, 0 mph.

I hope it helps you!          

Answer:

Stop going on peoples pages and  answering random things kid, get a life

Learn to  solve  problems instead

Explanation:

I answered this because this kid just goes on random pages, and answers incorrectly for points. Check this egirl wannabe's profile

Answer:

10 pa

Explanation:

4kg* 10 (or 9.8m/s2) = 40

40N /4m2 =10

Answer:

shushhhgggvvv vgfxgh

Explanation:

gey laahhg

there u go fella hope u understood

Answer:

Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.

Answer:

the force of resistance on the right team is 360 N

Explanation:

Given;

force of the left team, = 1000 N

total mass of the right team, m = 300 kg

acceleration of the right team, a = 1.2 m/s²

The force of resistance of the right team is calculated as;

Force = mass x acceleration

Force, F = 300 x 1.2

Force = 360 N

Therefore, the force of resistance on the right team is 360 N

Answer:

the tension of the rope is 34.95 N

Explanation:

Given;

length of the rope, L = 3 m

mass of the rope, m = 0.105 kg

frequency of the wave, f = 40 Hz

wavelength of the wave, λ = 0.79 m

Let the tension of the rope = T

The speed of the wave is given as;

[tex]v = f\lambda = \sqrt{\frac{T}{\mu} } \\\\where;\\\\\mu \ is \ mass \ per \ unit \ length\\\\\mu = \frac{0.105}{3} = 0.035 \ kg/m\\\\v = f\lambda = 40 \times 0.79 = 31.6 \ m/s\\\\v = \sqrt{\frac{T}{\mu} } \\\\v^2 = \frac{T}{\mu} \\\\T = v^2 \mu\\\\T = (31.6^2)(0.035)\\\\T = 34.95 \ N[/tex]

Therefore, the tension of the rope is 34.95 N

Answer:

the DISTANCE between the lever arm and the force is always 90º

Explanation:

In this exercise, you are asked to complete the missing words so that the phrase makes sense.

note that the torque is

              τ = F x r

where bold indicates vectors

When the rope is pulled, the DISTANCE between the lever arm and the force is always 90º

Answer:

"the plants had already started growing."

Explanation:

I think this is the answer because the definition of a dependent variable is the variable that is being affected by the change. Since the plants had already started growing BECAUSE of "They ran out of the farmer's compost, so

some of the plants received that compost

when the seeds were planted and other

plants got hardware store compost after

the plants had already started growing."

Sorry if I am wrong, I am just a 4th grader, pls don't hate on me, I am just trying to help :)

Answer:

It's compost

Explanation:

In case you needed the dependent variable, its the amount of plant growth

Answer:

[tex]\mu=0.39[/tex]

Explanation:

From the question we are told that:

Angle [tex]\theta=28[/tex]

Acceleration [tex]a=1.25m/s^2[/tex]

Generally the equation for Frictional force  is mathematically given by

[tex]F=\muN[/tex]

Where

[tex]N=mgcos \theta[/tex]

[tex]N=mgcos 28[/tex]

Since

Friction force is acting against move of box

Therefore

[tex]mgsin(28) - 1.25m = \mu mgcos(28)[/tex]

[tex]\mu=\frac{gsin(28) - 1.25}{gcos(28)}[/tex]

[tex]\mu=0.39[/tex]

Answer:

Explanation:

This is a recoil problem, which is just another application of the Law of Momentum Conservation. The equation for us is:

[tex][m_av_a+m_ev_e]_b=[m_av_a+m_ev_e]_a[/tex] which, in words, is

The momentum of the astronaut plus the momentum of the piece of equipment before the equipment is thrown has to be equal to the momentum of all that same stuff after the equipment is thrown. Filling in:

[tex][(90.0)(0)+(.50)(0)]_b=[(90.0)(v)+(.50)(-4.0)]_a[/tex]

Obviously, on the left side of the equation, nothing is moving so the whole left side equals 0. Doing the math on the right and paying specific attention to the sig fig's here (notice, I added a 0 after the 4 in the velocity value so our sig fig's are 2 instead of just 1. 1 is useless in most applications).

0 = 90.0v - 2.0 and

2.0 = 90.0v so

v = .022 m/s This is the rate at which he is moving TOWARDS the ship (negative was moving away from the ship, as indicated by the - in the problem). Now we can use the d = rt equation to find out how long this process will take him if he wants to reach his ship before he dies.

12 = .022t and

t = 550 seconds, which is the same thing as 9.2 minutes

Answer:

[tex]T=7.5*10^{-5}[/tex]

Explanation:

From the question we are told that:

Radius [tex]r=2cm[/tex]

Work done [tex]W=1.5×10^-4 joules[/tex]

Generally the equation for Work done is mathematically given by

 [tex]W=T.dA[/tex]

Therefore

 [tex]T=\frac{W}{dr}[/tex]

 [tex]T=\frac{1.5*10^{-4}}{2}[/tex]

 [tex]T=7.5*10^{-5}[/tex]

Answer:

Explanation:

En la historia de la ciencia se han dado auténticas barbaridades. Pruebas con animales que hoy no perdonaría nadie, o investigaciones de conducta con personas como la de la cárcel de Stanford, que se han saldado como una especie de pasado incómodo sobre los límites de la experimentación. Sin embargo, pocos se pueden acercar por su carácter perturbador al denominado experimento de Little Albert o Pequeño Albert: El salvaje intento por probar con un bebé que las fobias pueden ser condicionadas y aprendidas. Y lo que es peor, conseguirlo.

Esta idea surgió de la mente de John Broadus Watson, reconocido padre de la rama conductista de la psicología, que desde 1913 había comenzado a probar en animales sus tesis. Estas bebían directamente del los estudios de Iván Pavlov, fisiólogo ruso que ganó el Nobel en 1904 por sus estudios sobre el sistema digestivo, pero que también sentó precedentes sobre la psicología.

link por si te interesa:

https://hipertextual.com/2017/10/pequeno-albert

Answer:

10 litres.

Explanation:

The air fuel ratio for aircraft is 12:1. It is due to simplicity piper archer is equipped with continuous flow injection system. There is a fuel sensing is Piper Archer which informs the pilot about the low fuel when the fuel level reaches to as low as 10 litres only in the tank. The yellow low furl light will illuminate to alert the pilot.

Answer:

1) Disolver azúcar en agua - Cambio químico - Es un caso de una solución en donde el solvente es el azúcar y el soluto es el agua.

2) Freir una chuleta - Cambio físico - Es un proceso de cocinado por un transferencia de calor y transferencia de masa.

3) Arrugar un papel - Cambio físico - Se aplica fuerzas externas para deformar el papel.

4) El proceso de la digestión - Cambio químico - Reducción de los alimentos a desechos y la absorción de nutrientes por el contacto con jugos gástricos o ambientes intestinales.

5) Secar la ropa al sol - Cambio físico - El secado es un fenómeno de transferencia de masa.

6) Congelar una paleta de agua - Cambio físico - Cambio del estado líquido al estado sólido por transferencia de calor.

7) Hacer un avión de papel - Cambio físico - Aplicación de fuerzas externas para plegar y doblar la hoja de papel.

8) Oxidación del cobre - Cambio químico - Proceso de corrosión por contacto con iones que se transportan en el ambiente.

9) Romper un lápiz - Cambio físico - Proceso de ruptura por esfuerzo normal a causa de un momento como consecuencia de una fuerza externa aplicada sobre el lápiz.

10) Prender fuegos artificiales - Cambio químico - Reacción química de reducción-oxidación.

11) Excavar un hoyo - Cambio físico - Remoción de tierra por trabajo físico.

12) Quemar basura - Cambio químico - Reacción de combustión.

Explanation:

A continuación, veremos que representa cada caso:

1) Disolver azúcar en agua - Cambio químico - Es un caso de una solución en donde el solvente es el azúcar y el soluto es el agua.

2) Freir una chuleta - Cambio físico - Es un proceso de cocinado por un transferencia de calor y transferencia de masa.

3) Arrugar un papel - Cambio físico - Se aplica fuerzas externas para deformar el papel.

4) El proceso de la digestión - Cambio químico - Reducción de los alimentos a desechos y la absorción de nutrientes por el contacto con jugos gástricos o ambientes intestinales.

5) Secar la ropa al sol - Cambio físico - El secado es un fenómeno de transferencia de masa.

6) Congelar una paleta de agua - Cambio físico - Cambio del estado líquido al estado sólido por transferencia de calor.

7) Hacer un avión de papel - Cambio físico - Aplicación de fuerzas externas para plegar y doblar la hoja de papel.

8) Oxidación del cobre - Cambio químico - Proceso de corrosión por contacto con iones que se transportan en el ambiente.

9) Romper un lápiz - Cambio físico - Proceso de ruptura por esfuerzo normal a causa de un momento como consecuencia de una fuerza externa aplicada sobre el lápiz.

10) Prender fuegos artificiales - Cambio químico - Reacción química de reducción-oxidación.

11) Excavar un hoyo - Cambio físico - Remoción de tierra por trabajo físico.

12) Quemar basura - Cambio químico - Reacción de combustión.