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mihalych1998 [28]

3 years ago

10

Please help me with this question

1 answer:

Andrei [34K]3 years ago

6 0

Answer:

C

Explanation:

Ore is usually refined once digged out to make certain things

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A very loud train whistle has an acoustic power output of 100 W. If the sound energy spreads out spherically, what is the intens

valentina_108 [34]

Answer

given,

Power output of loud train = 100 W

Distance of intensity level from train= 100 m

I₀ = 10⁻¹² W/m²

Intensity of sound = ?

we know,

$I = \dfrac{P}{Area}$

$I = \dfrac{P}{4\pi r^2}$

$I = \dfrac{100}{4\pi 100^2}$

$I =7.957\times 10^{-4}\ W/m^2$

Intensity level

= $10 log(\dfrac{I}{I_0})$

= $10 log(\dfrac{7.975\times 10^{-4}}{10^{-12}})$

= $10 \times 8.900$

= 89 dB

7 0

3 years ago

Which phrases describe all the outer planets’ motion? Check all that apply.

uranmaximum [27]

Answer: slow revolution and fast rotation

Solar system has 8 planets. 4 inner rocky planets - Mercury, Venus, Earth and Mars and 4 outer gaseous planets - <u>Jupiter, Saturn, Uranus and Neptune.</u> The outer planets have few common features.

They are gaseous. There period of revolution is larger than the inner planets which means that they have slow revolution about the Sun. One day on the outer planets is smaller than the inner planets which means they have fast rotation.

<u>For example,</u> Jupiter has revolves around sun in 11.86 Earth years and rotates about axis in 9.8 Earth hours. Uranus revolves around sun in 84 Earth years and rotates on its axis 17.9 Earth hours.

8 0

3 years ago

Read 2 more answers

the system shown above is released from rest. if friction is negligible, the acceleration of the 4.0 kg block sliding on the tab

JulsSmile [24]

The acceleration of the first block (4 kg) is -9.8 m/s².

The given parameters:

<em>Mass of the first block, m₁ = 4.0 kg</em>
<em>Mass of the second block, m₂ = 2.0 kg</em>

The net force on the system of the two blocks is calculated as follows;

$m_2 g - T = m_1 a$

where;

<em>T </em><em>is the tension in the connecting string due weight of the first block</em>

$m_2 g - m_1 g = m_1 a\\\\a = \frac{m_2 g - m_1g}{m_1} \\\\a = \frac{g(m_2 - m_1)}{m_1} \\\\a = \frac{9.8(2-4)}{2} \\\\a = -9.8 \ m/s^2$

Thus, the acceleration of the first block (4 kg) is -9.8 m/s².

Learn more about net force on two connected blocks here: brainly.com/question/13539944

5 0

2 years ago

A spring stretches 5 cm when a 300-N mass is suspended from it. Calculate the spring constant in N / m .

rusak2 [61]

Answer:

Spring constant in N / m = 6,000

Explanation:

Given:

Length of spring stretches = 5 cm = 0.05 m

Force = 300 N

Find:

Spring constant in N / m

Computation:

Spring constant in N / m = Force/Distance

Spring constant in N / m = 300 / 0.05

Spring constant in N / m = 6,000

8 0

2 years ago

Explain how the basic unit are combined to give the derived units of force, velocity, pressure and work

LuckyWell [14K]

Velocity:

Velocity is change in displacement with respect to time:

$\frac{\Delta x}{\Delta t}$

Analysing the units, meters (displacement) and seconds (time) are basic units:

$\frac{m}{s}$

Therefore the unit of velocity is m/s

Force:

Newton's second law of motion:

$F = ma$

Kilogram (mass) is a basic unit, and accelerations unit can be found using the equation:

$a=\frac{\Delta v}{\Delta t}$

Analysing the units:

$\frac{\frac{m}{s}}{s}=\frac{m}{s^2}$

Therefore, the unit of force is:

$kg\frac{m}{s^2}$

Pressure:

Pressure is given by the equation:

$P=\frac{F}{S}$ where S is area of effect, F is force

Area for a basic rectangle (geometric shape is arbitrary for dimensional analysis) is found by multiplying two lengths:

$[l^2]=m^2$ , the unit of area

Dividing the aforementioned unit of force by the unit of area:

$\frac{kg\frac{m}{s^2}}{m^2}=\frac{kg}{ms^2}$ , the unit of pressure

Work:

Work is given by the equation:

$W=\vec{F}\cdot \vec{x}$ , (dot product may be assumed as normal multiplication for the purposes of unit analysis)

Knowing displacement's (x) unit is m:

$[W]=\frac{kgm}{s^2}m=\frac{kgm^2}{s^2}$ , the unit of work.

3 0

2 years ago