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3 years ago

A man jumps from a 45 m cliff into a large body of water. How long will he fall before he enters the wate

Physics

1 answer:

julia-pushkina [17]3 years ago

7 0

Answer:

about 2.5 seconds depending on if he jumps up and out or if he jumps out.

Explanation:

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Water is being boiled in an open kettle that has a 0.52-cm-thick circular aluminum bottom with a radius of 12.0 cm. If the water

tangare [24]

Answer:

$T_b=107.3784\ ^{\circ}C$

Explanation:

Given:

thickness of the base of the kettle, $dx=0.52\ cm=5.2\times 10^{-3}\ m$

radius of the base of the kettle, $r=0.12\ m$

temperature of the top surface of the kettle base, $T_t=100^{\circ}C$

rate of heat transfer through the kettle to boil water, $\dot Q=0.409\ kg.min^{-1}$

We have the latent heat vaporization of water, $L=2260\times 10^3\ J.kg^{-1}$

and thermal conductivity of aluminium, $k=240\ W.m^{-1}.K^{-1}$

So, the heat rate:

$\dot Q=\frac{0.409\times 2260000}{60}$

$\dot Q=15405.67\ W$

From the Fourier's law of conduction we have:

$\dot Q=k.A.\frac{dT}{dx}$

$\dot Q=k\times \pi.r^2\times \frac{T_b-T_t}{5.2\times 10^{-3}}$

where:

$A=$ area of the surface through which conduction occurs

$T_b=$ temperature of the bottom surface

$15405.67=240\times \pi\times 0.12^2\times \frac{T_b-100}{5.2\times 10^{-3}}$

$T_b=107.3784\ ^{\circ}C$ is the temperature of the bottom of the base surface of the kettle.

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4 years ago

1. Say whether the following statements are true or false and explain why:

tiny-mole [99]

Explanation:

A] TRUE

B] TRUE

C] FALSE

D] FALSE

E] TRUE

F] TRUE

G]FALSE

H] FALSE

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4 years ago

A student shoots a spitball with a perfectly horizontal velocity of 9.7 m/s from a height of 1.8 meters. How long will it take f

sergejj [24]

Answer:A student shoots a spitball with a perfectly horizontal velocity of 9.7 m/s from a height of 1.8 meters. How long will it take for the spitball to hit the ground?

(ignore air resistance) (include units and correct number of significant figures)

Explanation:La respuesta es porque esa es la respuesta, la respuesta al número es 9.7 1.8 Divide =53.888

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3 years ago

What is the magnitude of the orbital velocity of the earth in m/s?

Lana71 [14]

Circumference C=2πr
C=2π(1.5x10^8)=9.42x10^8 

In 365 Days there are 8760hr 

V=distance/time 

V=(9.42x10^8)/8760=107534.2km/hr

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3 years ago

Top-down processing is often used when one encounters an unfamiliar stimulus. Please select the best answer from the choices pro

Naddik [55]

The answer for this question would be B) False or the second option because top-down processing is NOT often used when one encounters an unfamiliar stimulus.

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3 years ago

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