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3 years ago

What's the answer plz help?!

Physics

2 answers:

Olegator [25]3 years ago

8 0

The answer is C.
Choice A and B describe a physical change rather than chemical. A chemical change creates new substances. And a homogeneous solution's materials can be separated. Boiling salt water for example would separate the water from the salt.

eimsori [14]3 years ago

6 0

I think the answer is c chemical change

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When a person speaks, a sound intensity is generated that is 600 times greater than when the person whispers. What is the differ

Charra [1.4K]

Answer:

Originally : Level = log I / I0

Currently: Level = 10 log I / I0

Level = 10 log 600 = 10 * 2.78 = 27.8

Note the term 1 bel = 10 decibels

5 0

3 years ago

A 50 g mass is freely hanging from a horizontal meter stick at a distance of 99 cm from the pivot. Calculate the weight force W

Neko [114]

Answer:

W = 0.49 N

τ = 0.4851 Nm

Force

Explanation:

The weight force can be found as:

W = mg

W = (0.05 kg)(9.8 m/s²)

W = 0.49 N

The torque about the pivot can be found as:

τ = W*d

where,

τ = torque

d = distance between weight and pivot = 99 cm = 0.99 m

Therefore,

τ = (0.49 N)(0.99 m)

τ = 0.4851 Nm

The pivot exerts a FORCE on the meter stick because the pivot applies force normally over the stick and has a zero distance from stick.

6 0

3 years ago

Yo-Yo man releases a yo-yo from rest and allows it to drop, as he keeps the top end of the string stationary. The mass of the yo

patriot [66]

To solve this problem it is necessary to use the conservation equations of both kinetic, rotational and potential energy.

By definition we know that

$KE + KR = PE$

Where,

KE =Kinetic Energy

KR = Rotational Kinetic Energy

PE = Potential Energy

In this way

$\frac{1}{2} mv^2 +\frac{1}{2} I\omega^2 = mgh$

Where,

m = mass

v= Velocity

I = Moment of Inertia

$\omega =$ Angular velocity

g = Gravity

h = Height

We know as well that $\omega = v/r$ for velocity (v) and Radius (r)

Therefore replacing we have

$\frac{1}{2} mv^2 +\frac{1}{2} I\omega^2 = mgh$

$[tex]h= \frac{1}{2} \frac{v^2}{g} +\frac{1}{2} \frac{I}{mg}(\frac{v}{r})^2$ [/tex]

$h= \frac{1}{2}v^2 ( \frac{1}{g} +\frac{I}{mg}\frac{1}{r^2} )$

$h= \frac{1}{2}0.75^2 ( \frac{1}{9.8} +\frac{2.9*10^{-5}}{(0.056)(9.8)}\frac{1}{(0.0064)^2} )$

$h = 0.3915m$

Therefore the height must be 0.3915 for the yo-yo fall has a linear speed of 0.75m/s

6 0

3 years ago

Absolute pressure in tank is P1 = 260 kPa and local ambient absolute pressure is P2 =100 kPa. If liquid density in pipe is 13600

Pavlova-9 [17]

Answer:

1.176m

Explanation:

Local ambient pressure(P1) = 100 kPa

Absolute pressure(P2)=260kPa

Net pressure=absolute pressure-local ambient absolute pressure

Net pressure=P1(absolute pressure)-P2(local ambient absolute pressure)

Net pressure=260-100=160kPa

Pressure= ρgh

160kPa=13600*10*h

h= $\frac{160000}{136000}$

h=1.176m

5 0

3 years ago

A typical adult human lung contains about 330 million tiny cavities called alveoli. Estimate the average diameter of a single al

Amanda [17]

Answer:

The average diameter of a single alveolus is 0.0222 cm.

Explanation:

Volume of the lung ,V= 1.9 L

$1 L = 1000 cm^3$

$1.9 L=1.9\times 1000 cm^3=1900 cm^3$

Number of alveoli in a human lung = $330\times 10^6$

Volume of single alveoli =v

$v\times 330\times 10^6=V$

$v=\frac{1900 cm^3}{330\times 10^6}$

$v=5.7575\times 10^{-6} cm^3$

The alveoli are spherical.

Radius of an alveolus = r

Volume of the sphere = $\frac{4}{3}\pi r^3$

$v=\frac{4}{3}\pi r^3$

$5.7575\times 10^{-6} cm^3=\frac{4}{3}\times 3.14\times r^3$

$r=0.0111 cm$

Diameter of the alveolus =d

d = 2r = 2 × 0.0111 cm = 0.0222 cm

The average diameter of a single alveolus is 0.0222 cm.

7 0

3 years ago