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4 years ago

What do ocean waves and sound waves have in common?

Physics

2 answers:

Anettt [7]4 years ago

7 0

Since they are both examples of moving waves, they both transmit energy.

eduard4 years ago

6 0

They both make sound.

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Airbags and safety belts can reduce injuries because they can

pashok25 [27]

Answer:

reduce the velocity of collision

5 0

3 years ago

Two parallel-plate capacitors have the same dimensions, but the space between the plates is filled with air in capacitor 1 and w

Aleks [24]

Explanation:

The capacitance in two parallel-plate capacitors is:

$C=\frac{K\epsilon_oA}{d}$

For air, we have $K_1=1$

For plastic, we have $K_2=2.25$

Hence:

$C_1=\frac{K_1\epsilon_oA}{d_1}=\frac{\epsilon_oA}{d_1}\\C_2=\frac{K_2\epsilon_oA}{d_2}=2.25(\frac{\epsilon_oA}{d_2})$

a) Recall that the potential difference between the plates is the same ( $V_1=V_2=V$ ). The electric field is given by:

$E_1=\frac{V_1}{d_1}=\frac{V}{d_1}\\E_2=\frac{V_2}{d_2}=\frac{V}{d_1}$

The potential difference is defined as:

$V_1=\frac{Q_1}{C_1}=V\\V_2=\frac{Q_2}{C_2}=V$

Replacing:

$E_1=\frac{Q_1}{C_1d_1}\\E_2=\frac{Q_1}{C_1d_2}\\\\E_1d_1=\frac{Q_1}{C_1}\\E_2d_2=\frac{Q_1}{C_1}\\E_1d_1=E_2d_2\\\frac{E_1}{E_2}=\frac{d_2}{d_1}$

b) The energy is defined as:

$U=\frac{1}{2}CV^2$

So:

$U_1=\frac{1}{2}C_1V_1^2=\frac{1}{2}C_1V^2\\U_2=\frac{1}{2}C_2V_2^2=\frac{1}{2}C_2V^2\\U_1=\frac{1}{2}\frac{\epsilon_oA}{d_1}V^2\\U_2=\frac{1}{2}\frac{2.25\epsilon_oA}{d_2}V^2\\\frac{0.88U_2d_2}{\epsilon_oA}=V^2\\\frac{2U_1d_1}{\epsilon_oA}=V^2\\\frac{0.88U_2d_2}{\epsilon_oA}=\frac{2U_1d_1}{\epsilon_oA}\\\frac{U_1}{U_2}=0.44\frac{d_2}{d_1}$

5 0

4 years ago

If a cup of coffee has temperature 95∘C95∘C in a room where the temperature is 20∘C,20∘C, then, according to Newton's Law of Coo

lina2011 [118]

Answer:

T = 76.39°C

Explanation:

given,

coffee cup temperature = 95°C

Room temperature= 20°C

expression

$T( t ) = 20 + 75 e^{\dfrac{-t}{50}}$

temperature at t = 0

$T( 0 ) = 20 + 75 e^{\dfrac{-0}{50}}$

T(0) = 95°C

temperature after half hour of cooling

$T( t ) = 20 + 75 e^{\dfrac{-t}{50}}$

t = 30 minutes

$T( 30 ) = 20 + 75 e^{\dfrac{-30}{50}}$

$T( 30 ) = 20 + 75 \times 0.5488$

T(30) = 61.16° C

average of first half hour will be equal to

$T = \dfrac{1}{30-0}\int_0^30(20 + 75 e^{\dfrac{-t}{50}})\ dt$

$T = \dfrac{1}{30}[(20t - \dfrac{75 e^{\dfrac{-t}{50}}}{\dfrac{1}{50}})]_0^30$

$T = \dfrac{1}{30}[(20t - 3750e^{\dfrac{-t}{50}}]_0^30$

$T = \dfrac{1}{30}[(20\times 30 - 3750 e^{\dfrac{-30}{50}} + 3750]$

$T = \dfrac{1}{30}[600 - 2058.04 + 3750]$

T = 76.39°C

4 0

3 years ago

Xavier is roller skating at 14 km/h and tosses a set of keys forward on the ground at 8 km/h. The speed of the keys relative to

JulijaS [17]

Answer:

22km/h

Explanation:

The speed of the keys relative to the ground will be given by the sum of speed of keys with respect to the ground and the speed of keys with respect to the skater

Given that the speed of keys with respect to the ground is 8 m/s while the speed of keys with respect to skater is 14 km/h then the relative speed which combines both speeds will be 8+14=22 km/hr

8 0

4 years ago

The continental crust covers _______ of the earth’s surface.

cestrela7 [59]

40% of the Earth's surface is covered by continental crust.

8 0

3 years ago

Read 2 more answers