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3 years ago

Select all the correct answers.

1 answer:

3 0

Anything that's dropped through air is somewhat affected by air resistance. But, out of that list, the leaf and the balloon are the items that will be affected by air resistance enough so that you can plainly see it.

If you spend some time thinking about it, you can kind of understand why airplane wings and boat propellers are shaped more like leafs and balloons than like bricks and rocks.

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A mass on the end of a spring undergoes simple harmonic motion. At the instant when the mass is at its maximum displacement from

Mrac [35]

Answer:

C) True. At maximum displacement, its instantaneous velocity is zero.

Explanation:

The simple harmonic movement is given by

x = A cos wt

Speed

v = - A w sin wt

At the point of maximum displacement x = A

A = A cos wt

cos wt = 1

wt = 0

We replace the speed

v = -Aw sin 0 = A w

Speed is maximum

Let's review the claims

A) False. Speed is zero

B) False. It can be determined

C) True. Agree with our result

D) False. When one is maximum the other is minimum

4 0

2 years ago

How can a budget help you set spending goals?

OlgaM077 [116]

When you are setting up your budget, it is easier to start by setting your budgeting amounts based on the average of your last three months of spending. Many budgeting programs can import past transactions and help you come up with the estimates that you need for your budget. Then you can begin to make adjustments after you have those initial amounts.

The two main goals are to spend less than you earn and to know where your money is going. Once you have a working budget you can work towards your other goals of saving money and getting out of debt. It is important to avoid theses common budgeting mistakes when setting up your budget.

7 0

3 years ago

Si el coeficiente de fricción cinética entre los neumáticos y el pavimento seco es de 0.80. ¿Cuál es la distancia mínima para de

vovangra [49]

Answer: 52.9 metros.

Explanation:

Podemos escribir la fuerza de fricción cinética como

F = μ*N

donde N es la fuerza normal entre el coche y el suelo, cuya magnitud es igual al peso en esta situación.

F = μ*m*g

donde m es la masa del coche y g es 9.8m/s^2

y sabemos que μ = 0.8

Por la segunda ley de Newton, sabemos que:

F = m*a

fuerza es igual a masa por aceleración.

a = F/m

entonces la aceleración causada por la fuerza de rozamiento es:

F = 0.8*m*g

a = F/m = (0.8*m*g)/m = 0.8*g.

Entonces ya encontramos la aceleración, hay que recordar que esta aceleración es en sentido opuesto a la sentido de movimiento, entonces podemos escribir la aceleración como:

a(t) = -0.8*g

Para la velocidad, podemos integrar sobre el tiempo para obtener.

v(t) = -0.8*g*t + v0

donde v0 es la velocidad inicial del auto = 28.7m/s

v(t) = -0.8*g*t + 28.8m/s

Ahora podemos encontrar el tiempo necesario para que la velocidad del coche sea cero, en ese momento, como deja de moverse, ya no tendremos rozamiento cinético, entonces no habrá aceleración y el coche se detendrá completamente.

v(t) = 0m/s = -0.8*9.8m/s^2*t + 28.8m/s

7.84m/s^2*t = 28.8m/s

t = (28.8m/s)/(7.84m/s^2) = 3.63 segundos.

Ahora vamos a la ecuación de movimiento, donde asumimos que la posición inicial del coche es 0m, así que no tendremos constante de integración.

p(t) = -(1/2)*(0.8*9.8m/s^2)*t^2 + 28.8m/s*t

Ahora podemos evaluar la posición en t = 3.63 segundos, y esto nos dara la distancia que el coche se movio mientras frenaba.

p(3.63s) = -(1/2)*(0.8*9.8m/s^2)*(3.63s)^2 + 28.8m/s*(3.63s) = 52.9 metros.

6 0

2 years ago

Shanai drove 40 miles to the west, then turned around and drove 70 miles to the east. Draw vectors that show each segment of her

Dmitry [639]

Well she drove 30 more miles to the east than the west but I don’t understand what u are asking

4 0

2 years ago

One speaker generates sound waves with amplitude A.

raketka [301]

Answer:

iv) It is 9x bigger than before

Explanation:

As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:

At = A + 4A -2A = 3 A

The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:

I = P/A

where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)

For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.

If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.

So, the statement iv) is the right one.

7 0

3 years ago