i really need help with this ​

Answer: To focus on a near object – the lens becomes thicker, this allows the light rays to refract (bend) more strongly. To focus on a distant object – the lens is pulled thin, this allows the light rays to refract slightly.

Explanation:

Answer:

a kinetic energy

Explanation:

because it is moving

Answer:

Pteropods are little mollusks (related to snails, slugs and squid) that drift around in ocean currents, feeding on nutrient-rich plankton. Their rich diet makes them delicious to many fish. Seals eat many fish, and sharks eat seals and fish, so there it is: not even 6 degrees of shark separation.

Explanation:

Answer:

B Is not a problem

But A is

Explanation:

its either he is long sighted

so he is able to read from far and not near so it's better he sees a doctor to get recommend glasses

The difference between the AC and the DC is that the AC current is always reversing. Option D

We have to know that the term generator has to do with a device that can be used in the production of electricity. The principle upon which the generator works is the principle of the electromagnetic induction.

Now we know that when we have a DC generator, the current that it is able to supply can be found to be constant but in the case of the AC generator, there is a constant change since the direction  is reversing.

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The electric current of an AC generator differs from that of a DC generator in that it constantly reverses direction.

The correct option is D.

A mechanical device known as an AC generator transforms mechanical energy into AC or alternating current electrical power. Periodically, the electrical current in an AC generator changes direction.

A mechanical device known as a DC generator transforms mechanical energy into DC or direct current electrical power. The electrical current in a DC generator flows in one direction.

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Answer: At several different levels, scientific awareness will enhance the quality of life, from the routine functioning of our daily lives to global issues. In energy, conservation, agriculture, health, transportation, communication, security, economics, recreation, and discovery, science informs public policy and personal decisions.

Explanation:

Hope This Helps! : )

Responder:

T = 0.25 segundos

f = 4 Hz

Explicación:

Paso uno:

datos dados

se nos dice que las partículas tardan 0,25 segundos en completar una vibración

por lo tanto, el período es de 0,25 segundos

¿Qué es un período de vibración?

Un período T es el tiempo necesario para que un ciclo completo de vibración pase por un punto determinado.

la expresión para el período se da a continuación.

T = 1 / f

¿Cuál es la frecuencia de vibración?

Básicamente, se refiere a la frecuencia con la que ocurren las vibraciones.

la frecuencia es una tasa, se expresa como la inversa del período

f = 1 / T

t = 1 / 0.25

f = 4 Hz

Answer:

When the elevator is accelerating downward, the person feels lighter due to the downward normal force being less than the person's weight.

Explanation:

A person riding in an elevator subjected to a series of unbalanced forces depending on the direction the elevator is travelling.

Two forces are acting on the person; the force of gravity and the upward normal force from the elevator.

When the elevator is going upwards with acceleration a, the person feels heavier than his normal weight, due to the upward normal force being greater than the person's weight. N = mg + ma

When the elevator is moving downwards with acceleration a, the person feels lighter due to the downward normal force being less than the person's weight. N = mg - ma

However, when the elevator is moving up or down at constant velocity ie. acceleration a = 0, the person experience a normal force equal to weight. N = mg

When the elevator is moving downwards with acceleration a = g, the person experiences weightlessness. N = (mg - mg) = 0

Responder:

1 hora 20 min

Explicación:

Paso uno:

datos dados

Durante los primeros 120 km, se nos dice que la velocidad es de 60 km / h.

sabemos que velocidad = distancia / tiempo

por lo tanto, distancia = velocidad * tiempo

deja que el tiempo sea ty la velocidad sea s

distancia = s * t

distancia = 60t -------------------- 1

Segundo paso:

Durante los segundos 80 km, se nos dice que la velocidad es de 90 km / h.

sabemos que velocidad = distancia / tiempo

por lo tanto, distancia = velocidad * tiempo

deja que el tiempo sea ty la velocidad sea s

distancia = s * t

desatancia = 90t ------------------- 2

La distancia total recorrida es de 200 km.

entonces 200 = 60t + 90t

200 = 150t

t = 200/150

t = 1,3 horas

Por lo tanto, el viaje tendrá una duración de 1 hora y 20 minutos aproximadamente.

calculating the area under the graph by dividing it

into a triangles and rectangles

A2 = 0.5 × h × b

= 0.5 × 10 × 5 = 25

A1 = 0.5 × 10 × 15 = 75

A4 = 0.5 × 15 × 10 = 75

A4 = h × b = 10 × 35 = 350

total displacement = 25 + 75 + 75 + 350 = 525

Answer:

All points to the left of zero are negative numbers. All points to the right of the zero are positive numbers. Zero is generally considered the center of the number line since both positive and negative numbers (more specifically integers) are considered to go to infinity. (Negative infinity or positive infinity)

Explanation:

Whoops sorry I accidentally commented the first time

Answer:

[tex]\boxed {\boxed {\sf m= 2 \ kg , \\a= 34 \ m/s^2, \\\F= 68 \ N}}[/tex]

Explanation:

The formula for force is:

[tex]F=m*a[/tex]

If we rearrange the formula to solve for a (acceleration), the formula becomes

[tex]\frac{F}{m} =a[/tex]

The force is 68 Newtons. Let's convert the units to make the problem easier later on. 1 N is equal to 1 kg*m/s², so the force of 68 N is equal to 68 kg*m/s².

The mass is 2 kilograms.

[tex]F=68 \ kg*m/s^2 \\m= 2\ kg[/tex]

Substitute the values into the formula.

[tex]\frac{68 \ kg*m/s^2}{2 \ kg} =a[/tex]

Divide. Note that the kilograms will cancel each other out (hence why we changed the units).

[tex]\frac{68 \ m/s^2}{2}=a[/tex]

[tex]34 \ m/s^2=a[/tex]

The acceleration is 34 meters per second squared.

Answer:

the same place you threw it from

Explanation

Answer:

70kg

Explanation:

Given parameters:

Gravitational force  = 700N

Unknown:

Mass of the person = ?

Solution:

The weight is gravitational force on the person and can be expressed as;

        W = mg

m is the mass

g is the acceleration due to gravity  = 10m/s²

 So;

        700 = m x 10

            m  = 70kg

Answer:

-9.8

Explanation:

EDGE 2021

The vertical acceleration of a dart is equal to the negative of acceleration due to gravity (- g). The vertical acceleration of the dart is equal to -9.8m/s². Therefore, option (1) is correct.

Acceleration due to gravity is the acceleration acquired by a body due to gravitational force. As gravity has both magnitude and direction, so it is a vector quantity. Acceleration due to gravity is expressed by the symbol 'g'. The SI unit of g is m/s² and the value of g (acceleration due to gravity) on the surface of the earth is 9.8 m/s².

Let us suppose a body with mass (m) is dropped from a height ‘h’ above the surface of the earth with mass (M), it starts to move downwards with an increase in velocity to the earth's surface.

The body starts to accelerate toward the earth’s center under the action of gravitational force which is at a distance ‘r’.

Then, ma = GMm/r²

a = GM/r²

Therefore, the value of the acceleration due to gravity (g) = GM/r2.

Any object freely falling to the surface of the earth has acceleration due to gravity is 9.8m/s².

If the object moves away from the surface of the earth then it experiences the gravitational pull of the earth. Therefore, the acceleration of dart vertically is equal to -g.

Therefore, the vertical acceleration of the dart is equal to -9.8m/s².

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Answer:

A)  R = F1 + F2

B) R = | F1 - F2 |

Explanation:

A) For forces acting in the same direction

we will add up the forces : lets assume the forces to be F1 , F2

Then the magnitude of the forces acting in the same direction will be

R = F1 + F2

B) For forces acting in the opposite direction

we will subtract the forces i.e. stronger force - weaker force . assuming the forces to be F1 , F2

Hence the magnitude of the resultant force = R = | F1 - F2 |

Answer:

The answer is F

Explanation:

F stands for Fluorine, which is an element and consists of one atom.

Answer:

f

Explanation:

i took quiz

Answer:

Title IX of the Education Amendments Act of 1972 is a federal law that states: "No person in the United States shall, on the basis of sex, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any education program or activity receiving Federal financial assistance."

Explanation:

Answer:

26.67 s

Explanation:

v = Velocidad final = 40 m/s

u = Velocidad inicial = 20 m/s

[tex]t_1[/tex] = Tiempo inicial = 20 s

[tex]t_2[/tex] = Tiempo empleado durante la aceleración

a = Aceleración

s = Desplazamiento del automóvil durante la aceleración = 200 m

De las ecuaciones lineales de movimiento tenemos

[tex]v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{40^2-20^2}{2\times 200}\\\Rightarrow a=3\ \text{m/s}^2[/tex]

[tex]v=u+at_2\\\Rightarrow t_2=\dfrac{v-u}{a}\\\Rightarrow t_2=\dfrac{40-20}{3}\\\Rightarrow t_2=6.67\ \text{s}[/tex]

El tiempo necesario para acelerar es 6.67 s

El tiempo total necesario para toda la ruta es [tex]t=t_1+t_2=20+6.67=26.67\ \text{s}[/tex].

Answer:

Celsius. i think! I might be wrong

Answer: Watts

Explanation: In the International System of Units (SI), thermal conductivity is measured in watts per meter-kelvin (W/(m•k)).

Answer: C

Explanation:

A: 100kg*0m/s (obviously not answer)

B: 20kg*2m/s (=40)

C: 5kg*50m/s (=250, safe bet this one is it)

D: 10kg*5m/s (=50)

5 kg at 50 m/s, with a momentum of 250 kg m/s has the most momentum.

Hence, the correct option is C.

To calculate momentum, we use the formula:

Momentum (p) = Mass (m) × Velocity (v)

Let's calculate the momentum for each option:

A. 100 kg at rest

Momentum = 100 kg × 0 m/s = 0 kg m/s

B. 20 kg at 2 m/s

Momentum = 20 kg × 2 m/s = 40 kg m/s

C. 5 kg at 50 m/s

Momentum = 5 kg × 50 m/s = 250 kg m/s

D. 10 kg at 5 m/s

Momentum = 10 kg × 5 m/s = 50 kg m/s

Therefore, 5 kg at 50 m/s, with a momentum of 250 kg m/s has the most momentum.

Hence, the correct option is C.

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You push against a wall, and the wall applies a force to your  hands. (A)

Answer:

The maximum height reached by the ball is 2.84 m

Explanation:

Given;

initial velocity of the soccer, u = 13 m/s

angle of projection, θ = 35°

The maximum height reached by the ball = ?

Apply the following kinematic equation, to determine the maximum height reached by the ball.

Maximum height (H) is given as;

[tex]H = \frac{U^2sin^2\theta}{2g} \\\\H = \frac{(13)^2(sin \ 35^0)^2}{2*9.8}\\\\H = 2.84 \ m[/tex]

Therefore, the maximum height reached by the ball is 2.84 m

Answer:

welding metal

Explanation:

Answer:

Workdone = 2906.25J

Explanation:

Given the following data;

Force, F = 155

Distance, d = 0.75

Stroke, s = 25

Mathematically, work done is given by the formula;

Work done = force * distance * stroke

[tex] W = F * d * s[/tex]

Where,

W is the work done

F represents the force acting on a body.

d represents the distance covered by the body.

s is the number of strokes.

Substituting into the equation, we have;

[tex] Workdone = 155*0.75*25[/tex]

Workdone = 2906.25J

True

Explanation:

Average speed is a scalar magnitude as opposed to average velocity which is a vector. The unit of measurement in the International System (S.I.) of the average speed is the meter per second (m/s).

Answer:

The circumference of planet tirth is [tex]C = 90000 \ km[/tex]

Explanation:

From the question we are told that

   The distance of tyene from the observer is  [tex]d = 750 \ km[/tex]

   The altitude of the sun from the equinox is   [tex]\theta_s = 87.0^o[/tex]

Generally given that on the equinox your sun is directly overhead in the city of tyene , then the altitude of the tyene from the equinox is  [tex]\theta_e = 90 ^o[/tex]

Generally the angular distance between tyene and the sun as observed from the equinox is mathematically represented as

         [tex]\theta _d = \theta_e - \theta_s[/tex]

=>       [tex]\theta _d = 90 -87[/tex]

=>       [tex]\theta _d =3^o[/tex]

Generally the ratio of [tex]\theta _d =3^o[/tex] to  [tex]360^o[/tex] which is the total angle in a circle is equal to the ratio of  [tex]d = 750 \ km[/tex] to the circumference of the planet

So

         [tex]\frac{\theta_d}{360} = \frac{750}{C}[/tex]

=>      [tex]\frac{3}{360} = \frac{750}{C}[/tex]

=>     [tex]C = 90000 \ km[/tex]