1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
andre [41]
3 years ago
11

Em muitas situações do dia a dia, temos que solucionar questões que exigem conhecimento das relações existentes entre as grandez

as físicas, seus múltiplos e submúltiplos. O exercício a seguir é um exemplo. Francisco, na sua chácara, próximo à sua casa de campo, separou uma área retangular de 150 m2 com 15 m de comprimento por 10 m de largura. Bem no centro dessa área será construída uma piscina. O fundo da piscina deve ser plano e horizontal com 1,5 m de profundidade. Observe o esquema que representa o projeto da construção da piscina e do seu entorno. Para tratar semanalmente a água da piscina, Francisco tem que utilizar 0,005 g de hipoclorito de sódio (cloro) a cada litro de água. Qual é o custo mensal com a cloração da água sabendo-se que um galão com 18 kg de hipoclorito custa R$135,00? Considere que um mês tenha 4,5 semanas.
Physics
1 answer:
VladimirAG [237]3 years ago
8 0

Answer:

R\$37,96

Explanation:

1) Olá, vamos calcular primeiramente o Volume da Piscina. Ela é uma piscina com uma forma tradicional, retangular. Temos a largura, o comprimento e a profundidade.

Volume=a.b.c\\\\Volume=largura*comprimento*altura\\Volume= 10*15*1,5\\Volume=225m^{3}

2) Precisamos fazer uma correlação entre a medida de capacidade (litro) e de volume, já que o custo é por litro d'água.

1 litro = 1dm^3\\1 m^{3}=1000 \:dm^{3}=1000 \:litros\\225\:m^{3}=225000\: litros

3) Observe que Francisco gasta 0,005 g de NaClO por semana.

Considerando que o mês tenha 4,5 semanas. E que quanto mais se trata a piscina mais se gasta Hipoclorito de Sódio. Temos uma relação diretamente proporcional.

Finalmente,

3.1) Rendimento do hipoclorito de produto em gramas por semana:

1 semana   \rightarrow      0,005g\\4,5 semanas  \rightarrow 0,0225g

3.2) Consumo mensal (y), considerando 4,5 semanas:

0,005g\rightarrow1 litro\\y\rightarrow225000\\y=1125 gramas \: para\: 225000 litros.\\\\1125gramas \:por\:litro\rightarrow 1 semana\\q \rightarrow 4,5\\q=5062,5 \:gramas=\:5,0625 Kg \:de \:NaClO\\\\

3.3)  O custo da manutenção, já que 18 kg de NaClO  custa R$ 135 e são grandezas diretamente proporcionais:

18 kg\rightarrow \$135\\5,0625  \:kg \:de \:NaOCl\rightarrow p\\p=\frac{5,0625*135}{18}=\frac{683.4375}{18} \therefore p=R\$37,96

You might be interested in
Under the Big Top elephant, Ella (2500 kg), is attracted to Phant, the 3,000 kg
Vladimir [108]

Under the Big Top elephant, Ella (2500 kg), is attracted to Phant, the 3,000 kg elephant. They are separated by 8

4 0
3 years ago
An above ground swimming pool of 30 ft diameter and 5 ft depth is to be filled from a garden hose (smooth interior) of length 10
STALIN [3.7K]

This question involves the concepts of dynamic pressure, volume flow rate, and flow speed.

It will take "5.1 hours" to fill the pool.

First, we will use the formula for the dynamic pressure to find out the flow speed of water:

P=\frac{1}{2}\rho v^2\\\\v=\sqrt{\frac{2P}{\rho}}

where,

v = flow speed = ?

P = Dynamic Pressure = 55 psi(\frac{6894.76\ Pa}{1\ psi}) = 379212 Pa

\rho = density of water = 1000 kg/m³

Therefore,

v=\sqrt{\frac{2(379212\ Pa)}{1000\ kg/m^3}}

v = 27.54 m/s

Now, we will use the formula for volume flow rate of water coming from the hose to find out the time taken by the pool to be filled:

\frac{V}{t} = Av\\\\t =\frac{V}{Av}

where,

t = time to fill the pool = ?

A = Area of the mouth of hose = \frac{\pi (0.015875\ m)^2}{4} = 1.98 x 10⁻⁴ m²

V = Volume of the pool = (Area of pool)(depth of pool) = A(1.524 m)

V = [\frac{\pi (9.144\ m)^2}{4}][1.524\ m] = 100.1 m³

Therefore,

t = \frac{(100.1\ m^3)}{(1.98\ x\ 10^{-4}\ m^2)(27.54\ m/s)}\\\\

<u>t = 18353.5 s = 305.9 min = 5.1 hours</u>

Learn more about dynamic pressure here:

brainly.com/question/13155610?referrer=searchResults

7 0
3 years ago
Why is it more difficult to lean over and push a heavy box across the floor than it is to attach a rope and pull the box at the
melisa1 [442]

Answer:

Case 1: <u>Pushing</u> Diagram 1

Leaning over and Pushing the heavy box from the floor, the push will be divided in to two parts, one is horizontal that can help the box move, and one is vertically downwards, which increases the downward force of the heavy object (an addition to the gravity) and thus increases friction, making it very hard to push.  When you push at certain angle, you are exhibiting two forces as shown in diagram 1.

  1. Horizontal force acting along the plane.
  2. Vertical force downward perpendicular to the surface.

Case 2: <u>Pulling</u> Diagram 2

Pulling on a rope similar object at the same angle, the pull can be divided into two parts, one is horizontal that can help the box move, and one is vertically upwards, which decreases the downwards force of the box (a subtraction in the gravity) and thus decreases friction, making it very easy to pull. When you pull at a certain angle, you are exhibiting two forces as shown in diagram 2.

  1. Horizontal force acting along the plane.
  2. Vertical force upward perpendicular to the surface.

So, in the case of pushing, it adds an extra weight on the object, which results in difficulty to push that object at the same angle.  In case of pulling, the upward perpendicular force, it tries to lift the  object upward and divided the weight partially. Thus making it easier to move the object at same angle.

8 0
3 years ago
Energy that a microwave use to heat food?
yanalaym [24]
Electromagnetic energy
6 0
3 years ago
An especially violent lightning bolt has an average current of 1.89 x 103 A lasting 0.133 s. How much charge is delivered to the
Rasek [7]
<h2> Charge = 25.9 Ampsec^{-1}</h2>

Explanation:

Given,

The average current (I) = {1.89} \times {103 A} and

Time period (T) = 0.133 s

The charge is calculated by multiplying the current to the time period.

Hence,

To find, the charge delivered to the ground by the lightning bolt(Q) = ?

By applying the formula of charge that is-

Charge(Q) = Current(I) \times Time(T)

∴ Charge(Q) = {1.89} \times {103 A}\times 0.133 s

= 25.89111 As^{-1}

= 25.9 As^{-}

<h3>Thus, the charge of 25.9 Ampsec^{-1} is delivered to the ground by the lightning bolt.</h3>
3 0
4 years ago
Other questions:
  • Determine the total impedance of an LRC circuit connected to a 10.0- kHz, 725-V (rms) source if L = 36.00 mL, R = 10.00 kΩ, and
    5·1 answer
  • According to Newton s Second Law of Motion, an object will accelerate if you apply what kind of force?
    14·1 answer
  • Check that equation 19.1 is dimensionally correct. the factor cw (specific heat of water is sometimes omitted because its numeri
    12·1 answer
  • What is the wave speed of a wave that has a frequency of 100 Hz and a wavelength of 0.30 m? please no bad answers
    10·1 answer
  • A sheet of aluminum (al) foil has a total area of 1.000 ft2 and a mass of 3.716 g. what is the thickness of the foil in millimet
    9·1 answer
  • A 2500-kg car falls over a cliff and converts 1000,000J of PE into KE.
    5·1 answer
  • The demand for your hand-made skateboards, in weekly sales, is q = −3p + 700 if the selling price is $p. You are prepared to sup
    7·1 answer
  • A 2 kg object is subjected to three forces that give it an acceleration −→a = −(8.00m/s^2)ˆi + (6.00m/s^2)ˆj. If two of the thre
    10·1 answer
  • A student claims an object in motion must experience a force to stay in motion. Do you agree or disagree?
    11·1 answer
  • Which statement is true about vectors?
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!