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DanielleElmas [232]

4 years ago

15

A harmonic wave is traveling along a rope. It is observed that the oscillator that generates the wave completes 37.6 vibrations

in 27.9 s. Also, a given maximum travels 450 cm along the rope in 11.3 s. What is the wavelength? Answer in units of cm.

1 answer:

tangare [24]4 years ago

8 0

Answer:

$\lambda = 25.79\ cm$

Explanation:

given,

Wave vibrates = 37.6

time = 27.9 s

maximum distance travel = 450 cm

time = 11.3 s

wavelength = ?

frequency of wave

$f=\dfrac{37.6}{27.9}$

f = 1.35 Hz

Speed of wave

$v = \dfrac{450}{11.3}$

v = 39.82 cm/s

wavelength of wave

v = fλ

$\lambda =\dfrac{v}{f}$

$\lambda =\dfrac{34.82}{1.35}$

$\lambda = 25.79\ cm$

Hence, wavelength of the wave is equal to 25.79 cm.

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Lerok [7]

Answer:

The near point of an eye with power of +2 dopters, u' = - 50 cm

Given:

Power of a contact lens, P = +2.0 diopters

Solution:

To calculate the near point, we need to find the focal length of the lens which is given by:

Power, P = $\frac{1}{f}$

where

f = focal length

Thus

f = $\frac{1}{P}$

f = $\frac{1}{2}$ = + 0.5 m

The near point of the eye is the point distant such that the image formed at this point can be seen clearly by the eye.

Now, by using lens maker formula:

$\frac{1}{f} = \frac{1}{u} + \frac{1}{u'}$

where

u = object distance = 25 cm = 0.25 m = near point of a normal eye

u' = image distance

Now,

$\frac{1}{u'} = \frac{1}{f} - \frac{1}{u}$

$\frac{1}{u'} = \frac{1}{0.5} - \frac{1}{0.25}$

$\frac{1}{u'} = \frac{1}{f} - \frac{1}{u}$

Solving the above eqn, we get:

u' = - 0.5 m = - 50 cm

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3 years ago

Sheila did 110 J of work to move a chair 2 m to the right. How much force did Sheila use to move the chair?

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An astronaut holds a rock 100m above the surface of Planet X . The rock is then thrown upward with a speed of 15m/s , as shown i

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Answer: $5 m/s^{2}$

Explanation:

The described situation is is related to vertical motion (and free fall). So, we can use the following equation that models what happens with this rock:

$y=y_{o}+V_{o}sin\theta t-\frac{1}{2}gt^{2}$ (1)

Where:

$y=0m$ is the rock's final height

$y_{o}=100 m$ is the rock's initial height

$V_{o}=15 m/s$ is the rock's initial velocity

$\theta=90\°$ is the angle at which the rock was thrown (directly upwards)

$t=10 s$ is the time

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Then, isolating $g$ and taking into account $sin(90\°)=1$ :

$g=(-\frac{2}{t^{2}})(y-y_{o}-V_{o}t)$ (2)

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Finally:

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3 years ago

Muitos remédios são tomados em doses menores que o mg. Um comprimido de certo remédio tem 0,025 mg de uma certa substância. Com

Sergio039 [100]

Answer:

Explanation:

<u>The question is asked in portuguese</u>

<u>Hence, it will be answered in portuguese</u>

1kg = 1000g

e

1 g = 1000mg

então

1 kg = 1 x (1000 x 1000)

1 kg = 1x 1.000.000

1 kg = 1.000.000mg

assim

1 comprimido -------------> 0,025 mg

x comprimido ------------> 1.000.000 mg ( só cruzar)

0,025(x) = 1(1.000.000)

0,025x = 1.000.000

x = 1.000.000/0,025

x = 40.000.000

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3 years ago

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Oksana_A [137]

Answer:

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Explanation:

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According to Newton's law of cooling;

$\frac{dT}{dt} \alpha (T-21)\\\\\frac{dT}{dt} = k (T-21)\\\\\frac{dT}{T-21} = kdt\\\\\int\limits {\frac{dT}{T-21}} = \int\limits kdt\\\\Log(T-21) =kt + Logc \\\\Log (\frac{T-21}{c} ) = kt\\\\T -21 = ce^{kt}\\\\At \ t = 0, T = 95\\\\95-21 = ce^0\\\\74 = c\\\\New, equation: T -21 = 74e^{kt}\\\\Again; when \ t= 5\ min, T = 80\\\\80 -21 = 74e^{5k}\\\\59 = 74e^{5k}\\\\e^{5k} = \frac{59}{74}\\\\ 5k = ln(\frac{59}{74})\\\\5k = -0.2265\\\\k = -0.0453$

When the temperature is 50 °C, the time t in min is calculated as;

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Therefore, when the temperature of the coffee is 50 °C, the time will be 20.68 mins

4 0

3 years ago