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3 years ago

3. A museum curator moves artifacts into place on various different display

Physics

1 answer:

Alex3 years ago

4 0

Explanation:

a. moving a 145 kg aluminum sculpture across a horizontal steel platform

b. pulling a 15 kg steel sword across a horizontal steel shield

c. pushing a 250 kg wood bed on a horizontal wood floor

d. sliding a 0.55 kg glass amulet on a horizontal glass display case

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What is the frequency of microwaves of wavelength 3 cm?

tiny-mole [99]

Answer:

10 GHz

Explanation:

Applying,

v = λf.................... Equation 1

Where v = speed of microwave, λ = wavelength, f = frequency.

make f the subject of the equation

f = v/λ................ Equation 2

Note: Microwave is an electromagnetic wave, and all electromagnetic wave have the same speed, which is 3×10⁸ m/s

From the question,

Given: λ = 3 cm = 0.03 m

Constant; v = 3×10⁸ m/s

Substitute these values into equation 2

f = 3×10⁸/(0.03)

f = 10¹⁰ Hz

f = (10¹⁰/10⁹) GHz

f = 10 GHz

4 0

3 years ago

Which is the best example of tropism in plants?

seraphim [82]

Answer:

Here are some examples of tropism in plants : Sunflowers are one of the best examples of positive phototropism , as they always grow facing the sun.

Explanation:

Although some experts consider that perhaps such a clear growth movement should not be considered tropism.

3 0

2 years ago

An airplane wing is designed so that the speed of the air across the top of the wing is 255 m/s when the speed of the air below

grin007 [14]

<h2>Answer:442758.96N</h2>

Explanation:

This problem is solved using Bernoulli's equation.

Let $P$ be the pressure at a point.

Let $p$ be the density fluid at a point.

Let $v$ be the velocity of fluid at a point.

Bernoulli's equation states that $P+\frac{1}{2}pv^{2}+pgh=constant$ for all points.

Lets apply the equation of a point just above the wing and to point just below the wing.

Let $p_{up}$ be the pressure of a point just above the wing.

Let $p_{do}$ be the pressure of a point just below the wing.

Since the aeroplane wing is flat,the heights of both the points are same.

$\frac{1}{2}(1.29)(255)^{2}+p_{up}= \frac{1}{2}(1.29)(199)^{2}+p_{do}$

So, $p_{up}-p_{do}=\frac{1}{2}\times 1.29\times (25424)=16398.48Pa$

Force is given by the product of pressure difference and area.

Given that area is $27ms^{2}$ .

So,lifting force is $16398.48\times 27=442758.96N$

6 0

3 years ago

If a trapezoidal channel has side slopes of 1:1, hydraulic depth is 5 feet, the bottom width is 8 feet, flow is 2,312 cubic feet

Evgesh-ka [11]

Answer:

$S = \dfrac{1}{2.5}$

Explanation:

given,

side slope = 1 : 1

hydraulic depth(y) = 5 ft

bottom width (b)= 8 ft

x = 1

Q = 2,312 ft³/s

n = 0.013

slope of channel = ?

$R = \dfrac{A}{P}$

$R = \dfrac{y(b + xy)}{b+2y\sqrt{1+x^2}}$

$R = \dfrac{5(8+ 5)}{8+2\times 5\sqrt{1+1^2}}$

R = 4.69 m

using manning's equation

$Q = \dfrac{1}{n}AR^{2/3} S^{1/2}$

$2312= \dfrac{1}{0.013}\times (5(8+5))\times 4.69^{2/3} S^{1/2}$

$2312=14009.37\times S^{1/2}$

S = 0.406

$S = \dfrac{1}{2.5}$

5 0

3 years ago

What is elasticity in polymer generally related to?

Andrej [43]

The elasticity of a polymer is primarily due to the structure of the molecule and the cross-linking between strands. Hydrogen bonding is a contributor to the shape of the molecule, but not a major player in terms of elasticity. We would have to answer "false".
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6 0

3 years ago

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