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3 years ago

What is air pressure?

2 answers:

8 0

Air pressure is the amount of molecules in the air. For example, the higher you go in Earth's atmosphere the less pressure so less molecules.

dalvyx [7]3 years ago

8 0

Air pressure also varies over time, and these temporal differences are usually caused by the temperature of the air. Cool air is denser (heavier) than warm air. Warm air is less dense (lighter) than cool air and will therefore rise above it. Areas of high pressure can be caused when cool air is sinking and pressing on the ground. At this time, the weather is usually dry and clear. In contrast, when warm air rises, it causes a region of low pressure. With low pressure, the weather is often wet and cloudy.
Air pressure varies over time and from place to place. If we travel up a mountain or go up in a hot air balloon, for example, the air pressure gets less the higher we go. We can explain this difference by comparing air pressure to a pile of blankets on your bed.

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You work for the city water department and need to pump 3400 liters/minute of water from a tank at ground level into a vented (i

umka21 [38]

Answer:

$P_E=46.2778\ kW$

$v=1.804\ m.s^{-1}$

Explanation:

Given:

flow rate of water, $\dot{V}=3400\ L.min^{-1}=3.4\ m^3.min^{-1}$

∵Density of water is 1 kg per liter

∴mass flow rate of water, $\dot{m}=3400\ kg.min^{-1}$

height of pumping, $h=75\ m$

efficiency of motor drive, $\eta=0.9$

diameter of pipe, $D =0.2\ m$

Now the power required for pumping the water at given conditions:

$P=\dot{m}.g.h$

$P=\frac{3400}{60} \times 9.8\times 75$

$P=41650\ W$

Hence the electric power required:

$P_E \times \eta=P$

$P_E \times 0.9=41650$

$P_E=46.2778\ kW$

Flow velocity is given as:

$v=\dot{V}\div a$

where: a = cross sectional area of flow through the pipe

$v=\frac{3.4}{60}\div (\pi.\frac{0.2^2}{4} )$

$v=1.804\ m.s^{-1}$

3 0

3 years ago

Tracy stands on a skateboard and tosses her backpack to her friend who is standing in front of her. Which best describes the acc

madreJ [45]

Answer:

Explanation:

It is less than the acceleration of the backpack because abs has a greater mass.

5 0

3 years ago

Water drops fall from the edge of a roof at a steady rate. a fifth drop starts to fall just as the first drop hits the ground. a

Alchen [17]

The height of the roof is 3.57m

Let the drops fall at a rate of 1 drop per t seconds. The first drop takes 5t seconds to reach the ground. The second drop takes 4t seconds to reach the bottom of the 1.00 m window, while the 3rd drop takes 3t s to reach the top of the window.

Calculate the distances traveled by the second and the third drops s₂ and s₃, which start from rest from the roof of the building.

$s_2=\frac{1}{2} g(4t)^2=8gt^2\\ s_3=\frac{1}{2} g(3t)^2=(4.5)gt^2$

The length of the window s is given by,

$s=s_2-s_3\\ (1.00 m)=8gt^2-4.5gt^2=3.5gt^2\\ t^2=\frac{1.00 m}{(3.5)(9.8m/s^2)} =0.02915s^2$

The first drop is at the bottom and it takes 5t seconds to reach down.

The height of the roof h is the distance traveled by the first drop and is given by,

$h=\frac{1}{2} g(5t)^2=\frac{25t^2}{2g} =\frac{25(0.02915s^2)}{2(9.8m/s^2)} =3.57 m$

the height of the roof is 3.57 m

8 0

3 years ago

Read 2 more answers

¿Cuál es la masa aproximada del aire en una habitación de 5.6 m * 3.8 m * 2.8 m?

Nady [450]

It would be 3.15 in meters

8 0

3 years ago

The acceleration due to gravity on the Moon is gM. Suppose an astronaut on the Moon drops an object from a height of H. The time

iris [78.8K]

Answer:

TE = sqrt(GM/GE)TM

Explanation:

To solve for this problem, you have to use the second kinematic equation and set the height equal to each other. Because the heights are equal, 1/2GETE^2 = 1/2GMTM^2. Rearrange the equation and you'll get the answer

5 0

3 years ago