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3 years ago

A ship is travelling due east at 30 km/hr and a boy runs across the deck

Physics

1 answer:

dsp733 years ago

8 0

Answer:

Vr = 20 [km/h]

Explanation:

In order to solve this problem, we have to add the relative velocities. We must remember that velocity is a vector, therefore it has magnitude and direction. We will take the sea as the reference measurement level.

Let's take the direction of the ship as positive. Therefore the boy moves in the opposite direction (Negative) to the reference level (the sea).

$V_{r}=30-10\\V_{r}=20 [km/h]$

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Missing part in the text of the problem:
"<span>Water is exposed to infrared radiation of wavelength 3.0×10^−6 m"</span>

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where
m=1.8 g is the mass of the water
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$\Delta T=2.5 K$ is the increase in temperature.

Substituting the data, we find
$Q=(1.8 g)(4.18 J/(gK))(2.5 K)=18.8 J=E$

We know that each photon carries an energy of
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where h is the Planck constant and f the frequency of the photon. Using the wavelength, we can find the photon frequency:
$\lambda = \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{3 \cdot 10^{-6} m}=1 \cdot 10^{14}Hz$

So, the energy of a single photon of this frequency is
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and the number of photons needed is the total energy needed divided by the energy of a single photon:
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3 years ago

A spring has a spring constant of 20 N/m. How much potential energy is stored in the spring as it stretched 0.20 m

makkiz [27]

The elastic potential energy (Ep) is given by $Ep = \frac{1}{2}*k*x^2$

Data:
Ep = ? (Joule)
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x (displacement) = 0.20 m

Solving:
$Ep = \frac{1}{2}*k*x^2$
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$\boxed{\boxed{Ep = 0.4\:J}}\end{array}}\qquad\quad\checkmark$

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2 years ago

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40V because it will provide the same amount of power.

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2 years ago

A ski jumper has a mass of 59.6 kg. She is moving with a speed of 23.4 m/s at a height of 44.6 meters above the ground. Determin

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Hello!

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Replacing:

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garik1379 [7]

Answer:

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