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3 years ago

Why does a person feel cooler under a rotating fan?

1 answer:

4 0

What a fan does is create a wind chill effect. ... By blowing air around, the fan makes it easier for the air to evaporate sweat from your skin, which is how you eliminate body heat. The more evaporation, the cooler you feel.

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Many scientists would argue that the reproductive system is the most important system in the body. Which of these would best def

Alchen [17]

Answer = A

Without reproduction humans would basically become extinct

4 0

3 years ago

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A solid block is attached to a spring scale. When the block is suspended in air, the scale reads 20.1 N; when it is completely i

Paha777 [63]

Answer:

A) $V = 4.92 \cdot 10^{-4} m^{3} = 492 cm^{3}$

B) $d = 4181.49 kg/m^{3} = 4.18 g/cm^{3}$

Explanation:

A) Using the Archimedes' force we can find the weight of water displaced:

$W_{d} = W_{a} - W_{w}$

Where:

$W_{a}$ : is the weight of the block in the air = 20.1 N

$W_{w}$ : is the weight of the block in the water = 15.3 N

$W_{d} = W_{a} - W_{w} = 20.1 N - 15.3 N = 4.8 N$

Now, the mass of the water displaced is:

$m = \frac{W_{d}}{g} = \frac{4.8 N}{9.81 m/s^{2}} = 0.49 kg$

The volume of the block can be found using the mass of water displaced and the density of the water:

$V = \frac{m}{d} = \frac{0.49 kg}{997 kg/m^{3}} = 4.92 \cdot 10^{-4} m^{3} = 492 cm^{3}$

B) The density of the block can be found as follows:

$d = \frac{W_{a}}{g*V} = \frac{20.1 N}{9.81 m/s^{2}*4.92 \cdot 10^{-4} m^{3}} = 4181.49 kg/m^{3} = 4.18 g/cm^{3}$

I hope it helps you!

6 0

4 years ago

A pitcher throws a 0.14-kg baseball toward the batter so that it crosses home plate horizontally and has a speed of 42 m/s just

kykrilka [37]

Answer

given,

mass of base ball = 0.14 kg

speed before it made the contact with the ball (V i) = 42 m/s

speed after batter hit the ball(V f) = - 48 m/s

impulse = change in momentum

= $m\times (V_f-V_i)$

= $0.14\times (-48-42)$

= -12.6 Kg m/s

Magnitude of impulse = 12.6 Kg m/s

Force = $\dfrac{impulse}{time}$

= $\dfrac{12.6}{0.005}$

Force = 2520 N

5 0

3 years ago

Two identical resistors are connected first in series and second in parallel. The equivalent resistances of the two types of con

trasher [3.6K]

Answer:

$\frac{R_{s} }{R_{p} } =\frac{R_{1} }{R_{2} }+\frac{R_{2} }{R_{1} } +2$

Explanation:

We have series and parallel combination of two resisters $R_{1}$ and $R_{2}$ .

Series combination is

$R_{s}= R_{1}+R_{2}$ and Parallel is $R_{p} = (\frac{1}{R_{1}}+\frac{1}{R_{2}} )^-1$

Now dividing series equivalent resistance by parallel resistance gives us

$\frac{R_{s} }{R_{p} } =\frac{R_{1} }{R_{2} }+\frac{R_{2} }{R_{1} } +2$ .

Note! series Combination is simply superposition of two elements (resisters in this case ) in a circuit.

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3 years ago

Which of the following has to happen before the eardrum begins to vibrate with the same frequency as the source of the sound wav

777dan777 [17]

I just took the test it is D

I am 100% sure

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3 years ago

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