What force is required to accelerate a block of mass 4 kg at 2m/s2 on a surface which has a frictional force of 2N.

A friend rides, in turn, the rims of three fast merry-go-rounds while holding a sound source that emits isotropically at a certa

Aliun [14]

Complete Question

The complete question is shown on the first uploaded image

Answer:

a

The Ranking of the curve according to their speed would be equal Rank because $v_1 =v_2 =v_3$

b

The first frequency would have a higher rank compared to the other two which will have the same ranking when ranked with respect to their angular velocities because

$w_1 >w_2 = w_3$

c

The ranking of the second third frequency would be the same but their ranking would be greater than that of the first frequency because

$r_2 =r_3 >r_1$

Explanation:

Mathematically Frequency can be represented as

$F = \frac{v}{\lambda}$

Where $\lambda$ is the wavelength and v is the velocity

Now looking at the diagram we see that

For the first frequency we have

Let the wavelength be $\lambda_1 = \lambda$ , and the frequency $F_1 = F$

For the second frequency

Let the wavelength be $\lambda_2 = 2 \lambda$ , and the frequency $F_2 = \frac{F}{2}$

For the third frequency

Let the wavelength be $\lambda_3 = 2\lambda$ , and the frequency $F_3 = \frac{F}{2}$

To obtain v for each of the frequency we make v the subject in the equation above for each frequency

So,

For the first frequency we have

$v_1 = \lambda_1 F_1 = \lambda F$

For the second frequency

$v_2 = \lambda_2 F_2 = 2 \lambda*\frac{F} {2} = \lambda F$

For the third frequency

$v_3 = \lambda_3 F_3 = 2 \lambda*\frac{F} {2} = \lambda F$

Hence

The Ranking of the curve according to their speed would be equal Rank because $v_1 =v_2 =v_3$

Mathematically angular speed can be represented as

$w = 2 \pi f$

For the first frequency we have

$w_1 = 2\pi F_1 = 2 \pi F$

For the second frequency

$w_2 = 2 \pi F_2 = 2 \pi \frac{F}{2} = \pi F$

For the third frequency

$w_3 = 2 \pi F_3 = 2 \pi \frac{F}{2} = \pi F$

Hence

The first frequency would have a higher rank compared to the other two which will have the same ranking when ranked with respect to their angular velocities because

$w_1 >w_2 = w_3$

Mathematically the relationship between the angular velocity and the linear velocity can be represented as

$v = wr$

=> $r = \frac{v}{w}$

Since the linear velocity is constant we have that

$r \ \alpha \ \frac{1}{w}$

This means that r varies inversely to the angular velocity ,What this means for ranking due to the radius is that the ranking of the second third frequency would be the same but their ranking would be greater than that of the first frequency because

$r_2 =r_3 >r_1$

5 0

3 years ago

Para fabricar la bicicleta de un niño pequeño se tiene en cuenta que la fuerza que puede desarrollar es menor que la de un adult

Georgia [21]

Answer:

a) El piñón debe tener 20 dientes.

b) La bicicleta avanza aproximadamente 1,759 metros por cada pedaleada completa.

Explanation:

a) El plato es el engranaje más grande que forma parte del sistema de transmisión, acompañando a la cadena y el piñón integrado a la rueda trasera. Asumiendo que no existen pérdidas por fricción seca y que las condiciones de lubricación del sistema de transmisión son óptimas tal que las pérdidas de potencia son despreciables. Además, supongamos que la bicicleta viaja a velocidad constante, entonces tenemos la siguiente identidad mediante las definiciones de trabajo y potencia:

$T_{P}\cdot \omega_{P} = T_{p}\cdot \omega_{p}$ (1)

Donde:

$T_{P}$ - Torque del plato, en newton-metros.

$T_{p}$ - Torque del piñón, en newton-metros.

$\omega_{p}$ - Rapidez angular del piñón, en radianes por segundo.

$\omega_{P}$ - Rapidez angular del plato, en radianes por segundo.

Sabiendo el hecho que tanto el plato y el piñón experimenta la misma velocidad tangencial, podemos simplificar (1) como sigue:

$\frac{T_{P}}{R_{P}} = \frac{T_{p}}{R_{p}}$ (1b)

Puesto que el radio de cada elemento y el número de dientes son, por separado, directamente proporcionales al número de dientes, modificamos (1b) así y tenemos la siguiente identidad, la cual equivale a su vez a la razón de desarrollo:

$\frac{T_{P}}{T_{p}} = \frac{N_{P}}{N_{p}} = \frac{R_{P}}{R_{p}} = \frac{\omega_{p}}{\omega_{P}}$ (1c)

Donde:

$N_{p}$ - Número de dientes del piñón, sin unidad.

$N_{P}$ - Número de dientes del plato, sin unidad.

Si tenemos que $r = 1,4$ y $N_{P} = 28$ , entonces tenemos que el número de dientes del piñón es:

$r = \frac{N_{P}}{N_{p}}$

$N_{p} = \frac{N_{P}}{r}$

$N_{p} = \frac{28}{1,4}$

$N_{p} = 20$

El piñón debe tener 20 dientes.

b) De acuerdo con la relación de desarrollo, por cada revolución realizada por el plato, el piñón realiza 1,4 revoluciones. Entonces, el avance realizado por la rueda trasera ( $s$ ), en metros, es igual al productor de la relación de desarrollo y la circunferencia de la rueda, es decir:

$s = r\cdot 2\pi\cdot R$ (1)

Donde $R$ es el radio de la rueda trasera, en metros.

Si conocemos que $r = 1,4$ y $R = 0,2\,m$ , entonces el avance realizado por la rueda trasera es:

$s = r\cdot 2\pi\cdot R$

$s = (1,4)\cdot (2\pi)\cdot (0,2\,m)$

$s \approx 1,759 \,m$

La bicicleta avanza aproximadamente 1,759 metros por cada pedaleada completa.

3 0

3 years ago

The air that flows over the top part of an airplane's wing moves faster than the air that flows across the bottom. This faster m

kaheart [24]

As an airplane moves through the air, its wings cause changes in the speed and pressure of the air moving past them. These changes result in the upward force called lift.

The Bernoulli principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in the pressure exerted by the fluid.

A wing is shaped and tilted so the air moving over it moves faster than the air moving under it. As air speeds up, its pressure goes down. So the faster-moving air above exerts less pressure on the wing than the slower-moving air below. The result is an upward push on the wing—lift!

4 0

3 years ago

An object that is farther from a converging lens than its focal point always has an image that is _____.

bearhunter [10]

Smaller in size (Pt. Sized)

5 0

3 years ago

You slide a chair across a rough, horizontal surface. The chair's mass is 18.8 kg. The force you exert on the chair is 156 N dir

Luda [366]

Answer:

626.612 J

Explanation:

Work done by friction on the chair is given as

W-ΔEk = W'..................... Equation 1

Where W' = Work done by friction on the chair, W = Work done on the chair by me, Ek = change in Kinetic energy of the chair as a result of the slide.

From the question,

W = FdcosФ.............. Equation 2

ΔEk = 1/2m(v²-u²)................ Equation 3

Where F = Force applied on the chair, d = distance of slide, Ф = angle between the force and the horizontal, m = mass of the chair, v = final velocity of the chair, u = initial velocity of the chair

Substitute equation 2 and equation 3 into equation 1

W' = FdcosФ-1/2m(v²-u²)........................ Equation 4

Given: F = 156, d = 5 m, Ф = 26°, m = 18.8 kg, v = 3.1 m/s, u = 1.3 m/s

Substitute into equation 4

W' = 156×5×cos26°-1/2×18(3.1²-1.3²)

W' = 701.06-74.448

W' = 626.612 J.

Hence the work done by friction = 626.612 J

8 0

3 years ago