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3 years ago

8

If a freely falling rock were equipped with a speedometer, by how much would its speed readings increase with each second of fal

l?

1 answer:

Klio2033 [76]3 years ago

5 0

Its speed reading would increase to 10 m/s every second

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Evgen [1.6K]

Answer:

mass

.

Explanation:

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3 years ago

Which of the following are electromagnetic waves? sound waves water waves ground waves light waves`

Paraphin [41]

Hello! Light waves are an example of electromagnetic waves. I hope this helps!

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3 years ago

A 2.64-kg copper part, initially at 400 K, is plunged into a tank containing 4 kg of liquid water, initially at 300 K. The coppe

marin [14]

Answer:

a) $T_f=305.7049\ K$

b) $\Delta S=313.51\ J.K^{-1}$

Explanation:

Given:

mass of copper, $m_c=2.64\ kg$

initial temperature of copper, $T_{ic}=400\ K$

specific heat capacity of copper, $c_c=385\ J.kg^{-1}.K^{-1}$

mass of water, $m_w=4\ kg$

initial temperature of water, $T_{iw}=300\ K$

specific heat capacity of water, $c_w=4200\ J.kg^{-1}.K^{-1}$

a)

<u>∵No heat is lost in the environment and the heat is transferred only between the two bodies:</u>

Heat rejected by the copper = heat absorbed by the water

$2.64\times 385\times (400-T_f)= 4\times 4200\times (T_f-300)$

$T_f=305.7049\ K$

b)

<u>Now the amount of heat transfer:</u>

$Q=m_c.c_c.(T_{ic}-T_{f})$

$Q=2.64\times 385\times (400-305.7049)$

$Q=95841.5841\ J$

∴Entropy change

$\Delta S=\frac{dQ}{T}$

$\Delta S=\frac{95841.5841}{305.7049}$

$\Delta S=313.51\ J.K^{-1}$

5 0

4 years ago

In what way is the liquid water different from the water vapor?

just olya [345]

Answer:

The difference is the way the molecules are arranged and the way they move

Explanation:

Water molecules in liquid water are constantly sliding past and bumping into each other; they keep moving from one place to another. The molecules of water in water vapor are far apart and moving freely.

3 0

4 years ago

A mother hawk screeches as she dives at you. You recall from biology that female hawks screech at 785 Hz , but you hear the scre

Ludmilka [50]

Answer:

Speed of the hawk, v = 40.4 m/s

Explanation:

It is given that,

Exact frequency of the female, f = 785 Hz

Observed frequency of female, f' = 890 Hz

Speed of sound, v = 343 m/s

Let v' is the speed of the hawk. It is based on the concept of Doppler's effect. We know that when the object approaches you, its speed is given by :

$f'=f(\dfrac{v}{v-v'})$

$890=785\times (\dfrac{343}{343-v'})$

v' = 40.4 m/s

So, the speed of the hawk is 40.4 m/s. Hence, this is the required solution.

6 0

4 years ago