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3 years ago

15

Energy cannot be created nor destroyed, only changed from one form to another. How does listening to music on a radio obey the l

aw of conservation of energy?
Group of answer choices

Sound energy is changed into potential energy.

Electrical energy is converted into other forms of energy, such as sound.

Electrical energy remains unchanged.

Electrical energy is gradually destroyed as the radio plays.

1 answer:

Serhud [2]3 years ago

8 0

Answer: Electrical energy is converted into other forms of energy, such as sound.

Explanation: Using the law of conservation of energy we know that energy can never be destryped it can be transferred or be transformed into from one form to another.

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3)(20pts) Un barco invasor se encuentra a 560m de un puerto de defensa, el puerto tiene cañones que

Eduardwww [97]

a) Las balas de cañon disparadas desde el puerto deben tener una ángulo de 27.39° para que puedan impactar al barco, con una velocidad inicial de 82 m/s.

b) El tiempo de vuelo de las balas de cañon para alcanzar al barco que está a 560 m de distancia es de 7.69 s.

c) Sabiendo que el ángulo calculado en el inciso a) es para una distancia de 560 m, el barco debe estar a una distancia mayor para que las balas no lo alcancen.

a)

Podemos usar las ecuaciones de tiro parabólico para encontrar el ángulo que permita derribar al barco invasor.

$x=\frac{v_{i}^{2}sin(2\alpha)}{g}$ (1)

Donde:

v(i) es la velocidad inicial del cañon (82 m/s)
α es el ángulo de tiro
g es la gravedad (9.81 m/s²)
x es el desplazamiento total (560 m)

Lo que debemos hacer es depejar α de la ecuación 1

$sin(2\alpha)=\frac{xg}{v_{i}^{2}}$

$sin(2\alpha)=\frac{560*9.81}{82^{2}}$

$sin(2\alpha)=0.82$

$\alpha=\frac{sin^{-1}(0.82)}{2}$

$\alpha=27.39^{\circ}$

Por lo tanto, el ángulo para que el cañón impacte en el barco es de 27.39 °.

b)

Sabemos que la componente de la velocidad en el eje x es constante, así que podemo usar la siguiente ecuación.

$v_{x}=\frac{x}{t}$

La componente x de la velocidad es V(x) = V(i)cos(α) y sabiendo la distancia total de 560 m, el tiempo será:

$v_{i}cos(\alpha)=\frac{x}{t}$

$t=\frac{x}{v_{i}cos(\alpha)}$

$t=\frac{560}{82cos(27.39)}$

$t=7.69\: s$

El tiempo total de vuelo de las balas de cañon es de 7.69 s.

c)

Sabemos que el ángulo calculado en el inciso a) es de 27.39 °, y ese valor fue calcualdo para una distancia de 560 m, por lo tanto el barco debe estar a una distancia mayor que esa para que las balas no lo alcancen.

Puedes encontrar más información sobre tiro parabólico aquí:

https://brainly.lat/tarea/3605927

Espero te haya sido de ayuda!

3 0

3 years ago

Which of the following treatments would enhance the level of the Pfr form of phytochrome?A) exposure to far-red lightB) exposure

puteri [66]

Answer:

B) exposure to red light

Explanation:

Plants use a phytochrome system to sense the level, intensity, duration, and color of environmental light do as to adjust their physiology.

The phytochromes are a family of chromoproteins with a linear tetrapyrrole chromophore, similar to the chlorophyll. Phytochromes have two photo-interconvertible forms: Pr and Pfr. Pr absorbs red light (~667 nm) and is immediately converted to Pfr. Pfr absorbs far-red light (~730 nm) and is quickly converted back to Pr. Absorption of red or far-red light causes a massive change to the shape of the chromophore, altering the conformation and activity of the phytochrome protein to which it is bound. Together, the two forms represent the phytochrome system.

4 0

4 years ago

Only some shortwave radiation from the Sun reaches Earth’s surface. What is the leading cause of this radiation loss? Only some

anastassius [24]

Answer: Reflection by clouds

Explanation:

Only some shortwave radiation from the sun reaches the Earth's surface because solar radiation is being reflected by thick clouds and thin clouds transmit the solar radiation.

About 31 % of solar radiation is reflected by clouds. The tiny water particle scatters 20-90 % of incoming sunlight giving them a bright white appearance.

4 0

3 years ago

Why the dust particles undergoes small random movements? <br><br> Plz help!!?

Rashid [163]

Brownian motion<span> or pedesis is the </span>random motion<span> of particles suspended in a fluid </span>

8 0

3 years ago

A 80 kg skier grips a moving rope that is powered by an engine and is pulled at constant speed to the top of a 25 degrees hill.

zloy xaker [14]

Answer:

$P=28.085\,hp$

Explanation:

Given that:

mass of 1 skier, $m=80kg$

inclination of hill, $\theta=25^{\circ}$

length of inclined slope, $l=220m$

time taken to reach the top of hill, $t=2.3 min= 138 s$

coefficient of friction, $\mu=0.15$

<em>Now, force normal to the inclined plane:</em>

$F_N=m.g.cos\theta$

$F_N=80\times 9.8\times cos25^{\circ}$

$F_N=710.54\,N$

<em>Frictional force:</em>

$f=\mu.F_N$

$f=0.15\times 710.54$

$f=106.58\,N$

<em>The component of weight along the inclined plane:</em>

$W_l=m.g.sin\theta$

$W_l=80\times 9.8\times sin25^{\circ}$

$W_l=331.33\,N$

<em>Now the total force required along the inclination to move at the top of hill:</em>

$F=f+W_l$

$F=106.58+331.33$

$F=437.91\,N$

<em>Hence the work done:</em>

$W=F.l$

$W=437.91\times 220$

$W=96340.80\,J$

<em>Now power:</em>

$P=\frac{W}{t}$

$P=\frac{96340.80}{138}$

$P=698.12\,W$

<u>So, power required for 30 such bodies:</u>

$P=30\times 698.12$

$P=20943.65\,W$

$P=\frac{20943.65}{745.7}$

$P=28.085\,hp$

8 0

3 years ago