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3 years ago

Convection is the rising of

1 answer:

8 0

Since the outer plumage of the penguin can resist the flow of heat in the cold antarctic air they might gain a little of this heat to keep them warm by thermal convection.

<u>Explanation:</u>

Convection is the circular movement that happens when hot air/liquid moves with molecules that were fast, making it less dense rises while the cold air/liquid drops down.

Also, they follow the technique of standing together always in a group which further helps them to decrease the loss of heat between them.

The plumage of penguin provides 80 percent of total insulation and is highly resistant to wind penetration.

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A bicyclist bikes the 90 mi to a city averaging a certain speed. The return trip is made at a speed that is 1 mph slower. Total

Lynna [10]

Answer:

his speeds while going to city is 10 mph and while his round trip the speed will be 9 mph

Explanation:

Let say the speed of the bicycle while he moves towards the city is "v"

now the speed of the round trip must be smaller by 1 mph

so its speed for round trip will be

$v_2 = v - 1$

now we know that total time of the motion is 19 hr

so we will have

$t_1 = \frac{90}{v}$

$t_2 = \frac{90}{v - 1}$

so we will have

$t_1 + t_2 = 19 hr$

$\frac{90}{v} + \frac{90}{v-1} = 19$

$90(2v - 1) = 19(v^2 - v)$

$19 v^2 - 199 v + 90 = 0$

by solving above equation we have

$v = 10 mph$

so his speeds while going to city is 10 mph and while his round trip the speed will be 9 mph

5 0

3 years ago

What is a property of “normal force”? a. It always points perpendicular to the contact surface. b. It always points parallel to

OleMash [197]

Answer:

a. It always points perpendicular to the contact surface.

Explanation:

"Normal" means perpendicular. Normal forces are always perpendicular to the contact surface.

6 0

3 years ago

A 0.500-kg stone is moving in a vertical circular path attached to a string that is 75.0 cm long. The stone is moving around the

Semenov [28]

Answer:

B. 7.07 m/s

Explanation:

The velocity of the stone when it leaves the circular path is its tangential velocity, $v$ , which is given by

$v=\omega r$

where $\omega$ is the angular speed and $r$ is the radius of the circular path.

$\omega$ is given by

$\omega = 2\pi f$

where $f$ is the frequency of revolution.

Thus

$v=2\pi fr$

Using values from the question,

$v=2\pi\times 1.50\times0.75$

<em>Note the conversion of 75 cm to 0.75 m</em>

$v=2\times3.14\times 1.50\times0.75 = 9.42\times0.75 = 7.065=7.07$

6 0

3 years ago

While running around the track at school, Milt notices that he runs due East on the 100m homestretch and due West on the 100m ba

Yuri [45]

Answer a would be correct since velocity is a vector and has a magnitude and a direction. In this case v₁ = - v₂.

8 0

3 years ago

Read 2 more answers

determine the pressure exerted on the surface of a submarine cruising 175 ft below the free surface of the sea. assume that the

Alenkasestr [34]

Answer:

92.81 psia.

Explanation:

The density of water by multiplying its specific gravity by the density of sea water.

SG = density of sea water/density of water

ρ = SG x ρw

1 kg/m3 = 62.4 lbm/ft^3

= 1.03 * 62.4

= 64.27lbm/ft^3.

The absolute pressure at 175 ft below sea level as this is the location of the submarine.

P = Patm +ρgh

= 14.7 + 64.27 * 32.2 * 175

Converting to pound force square inch,

= 14.7 + 64.27 * (32.2ft/s^2) * (175ft) * (1lbf/32.2lbm⋅ft/s^2) * (1ft^2/144in^2 )

= 14.7 + 78.11 psia

= 92.81 psia.

8 0

3 years ago