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2 years ago

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1. A dog of mass 5 kg jumps on a table of mass 30 kg. As the dog walks around on the table, what is the average force that the t

able applies to the dog?

1 answer:

Oksana_A [137]2 years ago

5 0

Answer:

50N

The table is managing to keep the dog up, the dog is not moving up or down so the force that the table applies to the dog must be equal to the dogs weight - I draw this conclusion from Newton's 3rd law.

W= mg

W = 5 × 9.8

W = 49N

round to.one significant figure = 50N

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On a hot summer day, 3.50 ✕ 106 J of heat transfer into a parked car takes place, increasing its temperature from 36.5°C to 44.4

anygoal [31]

Answer:

a) $\Delta s=443037.9747\ J.K^{-1}$

b) $\Delta s=31868131.8681\ J.K^{-1}$

Explanation:

a)

Given:

amount of heat transfer occurred, $dQ=3.5\times 10^6\ J$

initial temperature of car, $T_i=36.5+273=309.5\ K$

final temperature of car, $T_f=44.4+273=317.4\ K$

We know that the change in entropy is given by:

$\Delta s=\frac{dQ}{T_f-T_i}$

$\Delta s=\frac{3.5\times 10^6}{(44.4-36.5)}$ (heat is transferred into the system of car)

$\Delta s=443037.9747\ J.K^{-1}$

b)

amount of heat transfer form the system of house, $dQ=5.8\times 10^8\ J$

initial temperature of house, $T_i=23.5+273=296.5\ K$

final temperature of house, $T_f=5.3+273=278.3\ K$

$\Delta s=\frac{dQ}{T_f-T_i}$

$\Delta s=\frac{5.8\times 10^8}{278.3-296.5}$

$\Delta s=31868131.8681\ J.K^{-1}$

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3 years ago

In a pig caller can produce a sound intensity level of 107 dB. How many pig callers would be needed to generate an intensity lev

myrzilka [38]

Answer:

20 pig callers

Explanation:

Given that:

A pig caller produced intensity level of a sound = 107 dB

To find how many pig callers required to generate an intensity level of 120 dB;

we have:

120 dB - 107 dB = 13 dB

Taking the logarithm function;

$10 \ log \bigg(\dfrac{I}{I_o} \bigg) = 13 \ dB$

where;

$I_o$ = initial intensity

$log \bigg(\dfrac{I}{I_o} \bigg) = 1.3$

$\dfrac{I}{I_o}= 10^{1.3 }$

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I ≅ 20 pig callers

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2 years ago

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algol [13]

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3 years ago

Give an example of how the apparent motion of an object depends on the observers motion

QveST [7]

In a moving car the outside looks to be moving. however if viewed from the outside, the car appears to be moving. so motion is relative to the person observing.

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2 years ago

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Free_Kalibri [48]

Answer:

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Given

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Required

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